• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.50-50
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• 2022

Recently, the use of mulching film has increased in soybean cultivation. Polyethylene (PE) films and biodegradable films (BF) have the advantages of improving soil moisture retention, geothermal maintenance, and CO2 maintenance as well providing weed control. Furthermore, BFs are a material that can compensate for the shortcomings of PE because it has the ability to decompose naturally by soil microorganisms, sunlight, and geothermal heat. Many researches have been carrying out studies regarding the development of BFs for these very reasons. This study was conducted better understand which films are optimal for soybean cultivation after evaluations of soybean growth and film characteristics of various BFs. BFs Farmsbio (Farm Hannong), Heulgro Film (Sejin Bio), Vonto Film (Eco-Hansung), two unnamed biodegradable films (Seojin Bio and Taesung), and a PE film were used in this study. For the control plots, no mulching was used. Experimental fields were fertilized according to conventional cultivation methods, tilled, and then covered with either BFs or PE films. After 1 week, soybean (cv. Daechan) seeds were seeded. Germination rate and plant height were measured at weekly intervals after seeding. In addition, pH, EC, and decomposition and light transmittance levels of films were measured during the experimental period. Daily average temperatures and relative humidity in soils was measured during the experimental period. There was no significant difference in germination rates and plant height in both crops grown with BFs and PE films, but crops grown in the control plot had significantly lower germination rates and growth. Soil pH was not significantly different regardless of treatments (BF, PE, and non-mulching) at 14, 28, and 42 days after seeding. In general, the EC contents in the control plots was lower than in crops grown using BFs and PE films. With the exception of some BFs, light transmittance and decomposition levels of films did not, in general, increase up to 70 days after soybean seeding. Since this study is ongoing, we are continually investigating these parameters. The average daily moisture in soil was higher in crops grown with BFs and PE films than in the control plot. However, the daily average soil temperature was not consistent regardless of treatments. Therefore, the BFs used in this study can be used without negative impacts on soybean growth.

• Clean Technology
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• v.20 no.3
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• pp.205-211
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• 2014

Biomass-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. This article described the effect of the additions of oxo-biodegradable additive, 4 kinds of plant biomass, unsaturated fatty acid, citric acid in the properties of polyethylene films. Bio films were prepared using a variety of biomasses and tested for feasibility as a food packaging film. Mechanical properties such as tensile strength and percent elongation at break were evaluated. Husk biomasses from such as corn, soybean, rice, and wheat were pulverized using air classifying mill (ACM) and four different types of packaging films with thickness of $50{\mu}m$ were prepared using the pulverized biomass and low density polyethylene/linear low density polyethylene. The packaging film with wheat husk biomass was found to have greater mechanical properties of elongation and tensile strength than the other samples. Biodegradability of bio film was measured to be 51.5% compared to cellulose.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.43-47
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• 1997

This study was conducted to investigate the effects of various types of mulching materials for cutflower cultivation in statice. The results obtained were as follows ; The soil temperature mulched by black polyethylene film or rice straw was lower as 3$^{\circ}C$ than that of soil mulched by transparent polyethylene film or non - mulching in plastic house. The weed yield occurrenced on the soil mulched by black polyethylene film was lower than that mulched by transparent polyethyl one film and rice straw or non-mulching. The growth characteristics, those are plant height, leaf length and leaf width were not different among the mulching materials but in flower quality and yield of first grade, black polyethylene film produced better than others.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.29-29
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• 2011

폴리에스테르는 많은 분야에서 응용되어 사용되어지고 있으나 최근 더욱 우수한 물성이 각 분야에서 요구되어 지고 있다. Poly (ethylene naphthalate)(PEN)는 PET 주쇄의 벤젠고리에 나프탈렌으로 치환되어 강직성이 강화되어 PET보다 약 $50^{\circ}C$정도 높은 $T_g(117^{\circ}C)$와 $10^{\circ}C$정도 높은 $T_m(265^{\circ}C)$을 가져서 열적 안정성, 고강도와 저신도를 갖는다. PEN은 상대적으로 우수한 내열성과 환경호르몬을 포함하지 않아 인체에 무해하다는 이점 때문에 수유병이나 머그컵으로도 사용되어질 수 있다. 또한 탄산음료 용 bottle이나 맥주 bottle등은 높은 barrier성이 요구되어지기 때문에 PET에 비해 약 5배 높은 barrier 성을 가지는 PEN을 블렌드하여 사용하기도 한다. PEN의 내열성 및 기계적 강도를 더욱 우수하게 하고자 고분자 사슬을 가교할 수 있는데, 가교에는 열처리 또는 감마선, 전자선, 자외선 조사를 이용할 수 있는데 열에 의한 가교는 균일한 열전달과 고온이 필요하며 감마선 및 전자선 조사는 설비의 고비용과 방사선 노출 위험으로 인해 비친환경적이다. 반면에 자외선 조사법은 다루기 쉽고 비용이 적게 들고 친환경적인 장점을 가진다. 본 연구에서는 PEN film의 열안정성과 기계적 특성을 향상시키기 위해 자외선 조사를 이용하여 PEN film의 광가교를 수행하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.75-76
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• 2007

Poly-Si Schottky barrier Thin Film Transistor (SB-TFT) is manufactured with erbium silicided source/drain. High quality poly-Si film was obtained by crystallizing the amorphous Si film with Excimer laser annealing (ELA) method. The fabricated poly-Si SB-TFT devices showed low leakage current and large on/off current ratio. Moreover, the electrical characteristics were considerably improved by 3% $H_2/N_2$ gas annealing, which is attributed to the reduction of trap states at the grain boundaries and interface trap states at gate oxide/poly-si channel.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.193-198
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• 2008

A novel refractive index sensor, which consists of polymer channel waveguide overlaid with $TiO_2$ thin film, is demonstrated. To evaluate the fabricated sensor, we measured the polarimetric interference induced by concentration change of injected glycerol solution. Our experimental results show that thicker $TiO_2$ film improves the sensitivity of the polarimetric interferometer. For the fabricated waveguide with a 20 nm thick $TiO_2$ film, the measured index change to lead phase variation of $2{\pi}$ is $1.8{\times}10^{-3}$.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.301-303
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• 2006

• 수도
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• s.34
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• pp.50-53
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• 1986

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.320.2-320
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• 1997

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.292-298
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• 1997

These studies were conducted to verify the effect of the supplementary lighting by reflective film mulching and its establishment in the north side of greenhouse on the utility of light at tomato by means of investigating changes of leaf temperatures, stomatal features, transpiration rates and photosynthetic rates. Stomatal density of leaves were high in the reflective film mulching but sizes of stomata were not different. As the osmotic potential in rooting zone was low, the stomatal resistance was high, transpiration rate was low, and leaf temperature was increased by 40.62$^{\circ}C$. And also in the block of reflective film mulching photosynthetic rates were decreased hut chlorophyll contents were not different. Especially, there is an effect of controlling greenhouse whiteflies by treatment of reflective film mulching. It is thought that the reason of high quality or increasing yield at several crops by supplementary lighting, such as reflective film mulching, would be caused by influences of absorption and distribution of nutrients through high transpiration rate and photosynthesis which resulted from increase of stomata.