• 상하수도학회지
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• 제26권6호
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• pp.907-914
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• 2012

Flexible pipes take advantage of their ability to move, or deflect, under loads without structural damage. Common types of flexible pipes are manufactured from polyethylene (PE), polyvinyl chloride (PVC), steel, glass fiber reinforced thermosetting polymer plastic (GFRP), and aluminum. In this paper, we present the result of an investigation pertaining to the short-term behavior of buried polyethylene pipe. The mechanical properties of the polyethylene pipe produced in the domestic manufacturer are determined and the results are reported in this paper. In addition, vertical ring deflection is measured by the laboratory model test and the finite element analysis (FEA) is also conducted to simulate the short-term behavior of polyethylene pipe buried underground. Based on results from soil-pipe interaction finite element analyses of polyethylene pipe is used to predict the vertical ring deflection and maximum bending strain of polyethylene pipe.

• 농업과학연구
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• 제25권1호
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• pp.19-25
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• 1998

조생종 '쓰가루' 사과의 단기저장 중 품질유지를 위한 몇 가지 수확후 처리 효과를 살펴 출하시기조절을 위한 방안을 마련하고자 하였다. 저장한 과실의 품질은 수확후 처리보다는 숙기에 많은 영향을 받았다. 경도 및 내적 품질을 고려하였을 때 착색정도가 중간 단계인 과실이 저장에 유리하였다. 수확후 처리 중 단순 PE포장은 증산억제에 따른 무게감량 방지에 효과적이었으나 기타의 품질에 대한 효과는 뚜렷하지 않았다. 그러나 에틸렌제거제 포장처리는 과실품질 유지에 긍정적인 효과를 보여주었다. 특히 산 함량이 높게 유지되어 과실은 더욱 신선하였다. 본 연구 수행 중 $0-1^{\circ}C$ 저장온도에서 생리적 장해가 주로 악편부위에 발생하였으며 미숙한 상태의 과실일수록 그 정도가 심하였다. 증상은 부정형의 작은 반점이 형성되었으며 반점부위의 표피조직은 함몰되었는데 일부 과실은 수침증상의 반점이 비교적 크게 형성되기도 하였다. 따라서 앞으로의 연구에서는 '쓰가루' 사과의 적정 저장온도에 대한 보다 세밀한 검토가 필요하였다.

• 한국식품과학회지
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• 제28권3호
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• pp.482-489
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• 1996

건고추를 통고추와 분말고추로 구분하고 감마선 조사기법을 이용, 포장재별(통고추; PC 마대 및 PE/PC 마대, 분말고추; NY/PE - laminated film) 및 저장온도별 품질 안전성 시험을 수행하여 위생화와 장기 안전저장성을 검토하였다. 건고추(통고추)는 실온조건에서 6개월 저장후 기존의 PC마대로 단독포장한 경우에 중량변화, 해충발생, 변색, 성분변화 등의 품질열화로 상품가치를 완전 상실하였으나, PE/PC병용포장후 5-7.5 kGy 범위의 감마선 조사는 실온에서 2년간 장기 안전저장이 가능하였다. 7.5-10 kGy 조사된 분말고추에서도 실온 및 저온($5-10^{\circ}C$)에서 2년간 저장동안 양호한 위생적, 이화학적, 관능적 품질을 유지하였다.

• 폴리머
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• 제35권4호
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• pp.296-301
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• 2011

본 연구는 고내구성을 가진 고분자 전해질막을 제조하는 것으로 연료전지에 적용하기 위하여 poly(vinyl alcohol)을 주사슬부로 하여 poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA)를 다공성 polyethylene(PE) 막에 함침시켜 막을 제조하였다. 제조된 막을 함수율, 접촉각, FTIR, 이온교환용량, 이온전도도 메탄올 투과도 열 중량분석, 탄성계수 등의 측정을 통해 친수성 고분자가 함침된 막의 특성평가를 실시하였다. 접촉각 측정과 FTIR 분석을 통해 PE 막에 함침된 막에서의 친수성기의 존재를 확인하였다. PSSA-MA의 함량이 10 wt% 함침된 막의 경우, 이온교환 용량은 Nafion 115의 0.91보다 향상된 1.2 meq./g dry membrane을 얻었다. 또한 탄성계수의 경우 PE 막에 비하여 3~3.6 배 높은 강도를 나타내었으며, 함수율과 메탄올 투과 실험을 통해 PSSA-MA의 함량이 늘어남에 따라 높은 치수안정성과 낮은 메탄올 투과결과를 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.154-155
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• 2006

This paper describes a tracking test results for the organic polymers with PE(polyethylene) series by a declining method. After processing the 4 PE series insulations with different density, the tracking duration for each was measured and compared with that for ABS(acrylonitrile butadiene styrene). The surface condition of each specimen was carefully observed after the tracking test. As a result, HDPE showed excellent performance in tracking test.

• 한국식품저장유통학회지
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• 제4권2호
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• pp.139-146
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• 1997

The influence of packaging methods(0.03mmPE, 0.05mmPE, 0.1mmPVC, VACUUM) and marketing temperatures(2$0^{\circ}C$, 1$0^{\circ}C$) on the shelf-life and quality were investigated in yam(Dioscorea). Respiration, weight-loss and rotting-rate was reduced in polyethylene film packaging in the order of VACUUM, 0.1mmPVC, 0.05mmPE, 0.03mmPE and the effect was more outstanding at 1$0^{\circ}C$ than 2$0^{\circ}C$. The ethylene concentration of PVC packaging group was higher than that of other packaging methods, which was related with sprouting. firmness was higher in low-temperature than in room-temperature. PPO activity was lower in vacuum than in other packaging methods, which was associated with browning. The shelf-life of yam was the longest in vacuum Packaging, 3 weeks at 2$0^{\circ}C$ and more than 4 weeks at 1$0^{\circ}C$.

• Journal of Welding and Joining
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• 제16권2호
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• pp.48-56
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• 1998

This study was performed to find the best bonding conditions by comparing mechanical properties in thermoplastic resin of polyethylene (PE) and polyamide (PA) adhesion. Following results were obtained from the tests with varying welding time and welding pressure. Satisfactory adhesion was executed in ultrasonic welding for the same materials of PE and PA. The best welding conditions were found to be welding time of 1 second, welding pressure of 250kPa for PE-PE weding, 2 second and 350kPa for PA-PA welding. Welding time and welding pressure end to increase with the increase of materials strength. Dissimilar materials were adhered when adhesion and ultrasonc welding were performed simultaneously. The observation of the structure of ultrasonic welding area with microscope showed differenticated structures between well adhered region and badly adhered region.

• 한국환경과학회지
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• 제11권4호
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• pp.327-332
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• 2002

Optical microscope, SEM (Scanning Electron Microscopy) and fluorescent microscope were used for qualitative and morphological studies of the attached biomass on PE (polyethylene) substratum under anaerobic condition. It was shown by the observation of optical microscope that the initial attachment of biomass began in crevices of the surface of PE. The shape and structure of the attached biofilm could be observed by SEM photographs, but species of bacteria were and methanogens were not classified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation. It was estimated that methanogenic bacteria was also related to initial attachment of biomass under anaerobic condition.

• 한국식품저장유통학회지
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• 제5권2호
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• pp.154-161
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• 1998

Changes of free sugars and sugar alcohols of fresh shiitake were measured during storage. Shiitake were stored at 1$^{\circ}C$ and -4$^{\circ}C$, with non-packaging, wrapping, 0.03mm polyethylene(PE)film packaging(unpunched and punched, unprecooled and precooled before storage), 0.05mm PE film (vacuum packaging). Chanties of glycerol, arabitol and arabinose contents were not marked during storage. The content chanties of $\beta$-rhamnose, fructose, glucose, mannitol, sucrose and maltose were the smallest until 40days storage and were increased significantly after 40 days and then decreased significantly after 50days. Content of $\beta$-rhamnose during storage when was treated unprecooling, 0.03mm PE film punched and unpunched at -4$^{\circ}C$ was the highest 25.08% and 34.86%, respectively in 50~60days. Content of mannitol was not changed at -4$^{\circ}C$.

• Macromolecular Research
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• 제8권2호
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• pp.66-72
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• 2000

Cis-Polybutadiene (cis-PBD) and the three polyethylenes (PE's) having different branch content were mixed to investigate crystallinity, thermodynamic interaction parameter(c), and diluents effect. Crys-tallinty of PE's decreased with increasing content of amorphous cis-PBD because of a decrease in both the degree of annealing and kinetics of diffusion of the crystallizable polymer content. The thermodynamic interaction parameter(c) for the three blend systems approximately equals to zero near the melting point. These systems were determined to be miscible on a molecular scale near or above the crystalline melting point of the crystalline PE's. From the measurement of T$\sub$m/ vs. T$\sub$c/ behavior, all the three blends showed a straight line for a plot of T$\sub$m/ vs. T$\sub$c/. This result means that the melting behavior of PE is mainly due to a diluent effect of cis-PBD component.