• Korean Journal of Food Science and Technology
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• v.10 no.1
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• pp.8-10
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• 1978

After growing the hot pepper fruits in polyethylene film(PE) house covered with white or red colored film, the fruits were collected and chlorophyll, carotenoid, and capsaicin content was analyzed. Although total chlorophyll content was higher in fruit of white PE house$(208.9{\mu}g/g-F.W)$ as compared to that of red PE house $(153.0{\mu}g/g-F.W)$ grown plants, the ratio of chlorophyll a over b were similar, giving 2.15 and 2.13 respectively in white and red PE house. Total carotenoid, $\beta$-carotene and the capsaicin content were higher in fruits of red PE house grown plants. Therefore, it is suggested that red film could be used as a successful covering material for poly ethylene film house.

• Applied Biological Chemistry
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• v.20 no.3
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• pp.296-299
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• 1977

The blue, green, and red colored polyethylene film was used as a covering material for house grown pepper production to compare with the white film. Plant height was the tallest in red PE house(78.8 cm) followed by white, blue, and green PE house. The leaf weight was 0.40g in white PE house and 0.39g in red PE house which was higher than the weight in blue and green PE house. Fruiting percentage was 48.0% and 46.1% in white and red PE house, respectively, however no fruit was set in blue and green PE house. The fruit weight was 3.32g and 2.81g, in red and white PE house, respectively. The K, Ca, Mg, and Fe content in the leaf was the lowest in plants grown in white PE house. The content of K, Ca, Mg, and Fe was the highest in plants grown in green PE house.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.317-323
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• 1988

This survey was conducted to know characterization of weed occurrence under protected culture conditions at Yousong in 1985. Chenopodium album, Polygonum hydropiper, Portulaca oleracea and Digitaria sanguinalis were dominated in outdoor, whereas Capsella bursa-pastoris, C. album, D. sanguinalis and P. oleracea were dominant in polyethylene house. More weeds emerged in mulching plots and dry weight of weeds was greater in non-mulching plots. Summer broadleaf weeds and summer grasses were abundant in outdoor, whereas non-mulching plots in polyethylene house was dominated by winter broadleaf weeds, and mulching plots in polyethylene house were dominated by winter grasses and winter broadleaf weeds in early stage and summer grasses and summer broadleaf weeds in late stage. Simpson index was high in polyethylene house and Shannon's diversity index, maximum diversity for the Shannon diversity index were lower than eveness using the Shannon diversity index and this trend was more remarkable in mulching and mulching in tunnel than in non-mulching under polyethylene house condition. Shannon diversity index, maximum diversity for the Shannon diversity index were high in mulching or tunnel, and Simpson index was high in non-mulching in outdoor condition. Interspecific competition was more severe than intraspecific competition in both conditions.

• 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.

• Korean Journal of Plant Resources
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• v.12 no.1
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• pp.38-42
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• 1999

To obtained the basic information needed in the development of higher quality and yield of ginger, twenty-four indigenous colones of ginger were evaluated major agronomic characteristics under field and polyethylene house culture. There was highly significant differences in yield and 6-gingerol contents among the clones studied. Maximum yield was recorded in clone CG9579(3520kg/10a) followed by CG95134, CG9512, CG96109, CG9596, in field culture. The maximum 6-gingerol percentage was recorded in the clone CG9579 containing 4.44mg/g, and next was CG9583 4.35mg/g, CG95134 4.32mg/g DW. In addition, CG9503 and CG95105 clones showed more than 4,000kg/10a in polyethylene house culture.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.72-77
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• 2019

Vinyl house consists of main rafter, lateral member, clamps and polyethylene film. Many vinyl houses are used to grow fruits, flowers and vegetables in the countryside. Due to climate change, vinyl houses are often destroyed by strong winds or typhoons in summer. Many farmers suffer great economic damage from the collapse of vinyl houses. So it is very important to build a safe vinyl house and find a method to withstand this heavy wind load. In this study, a structural analysis was performed on four types of vinyl houses(10-single-4, 10-single-6, 10-single-7, 10-single-10). In addition, axial force and flexural moment are obtained from the structural analysis of four types of vinyl house. For these four types of vinyl house, structural safety was reviewed by obtaining the combined stress ratio by the strength design method. This structural review showed that the specifications for the vinyl house proposed in the design are not safe. Especially, the result of structural analysis for four types of vinyl house showed that the vinyl house structure constructed as a standard was a very dangerous structure. Therefore, it is necessary to devise diverse methods in order to make vinyl houses structurally safe for heavy wind load in the future. Also a variety of manual development is needed to prevent the collapse of vinyl houses at heavy wind load.

• Journal of the Korean Society of Safety
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• v.34 no.2
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• pp.34-39
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• 2019

Vinyl house consists of main rafter, lateral member, clamps and polyethylene film. Many vinyl houses are used in the countryside to grow vegetables. These vinyl houses have occasionally been collapsed due to heavy snowfall in winter. Many farmers get a lot of economical damages, if vinyl houses are collapsed. So it is most important to built a safe vinyl house that can withstand heavy snowfall. In this study, a structural analysis was performed on three types of vinyl houses(07-single-01, 10-single-04, 12-single-01). In addition, the structural analysis of the three types of vinyl houses provided axial forces, flexural moment, and combined stress. For these three types of vinyl houses, structural safety was reviewed by obtaining the combined stress ratio by the strength design method. This structural review showed that the specifications for the vinyl house proposed in the design are not safe. Especially, the result of increasing the design snow load by 15 percent and 30 percent showed that the vinyl house structure constructed as a standard for vinyl house was a more dangerous structure. Therefore, it is necessary to revise regulations such as increasing the thickness of rafters or widening the gap in order to make vinyl houses structurally safe for heavy snowfall in the future, and to devise diverse methods to make vinyl houses that are structurally safe.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.249-255
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• 1990

The conditions for separation and identification of anionic and nonionic surfactants by thin layer chromatography were investigated. Polyoxy alkylene-type nonionic surfactants were identified by the distribution of alkyl chain and alkylene oxide. Various polyoxyethylenated nonyl phenols were easily distinguished by densitometer. Some anionic surfactants were identified by $R_f$ and color, and the mixtures of anionic and nonionic surfactants were separated. Polyoxyethylenated fatty acid was separated into three parts of diester, monoester and polyethylene glycol, respectively, and the mixed ratio was determined by densitomer. All the experiments were carried out in 13-20 minutes, and the length of run was 80mm.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.380-384
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• 2010

Purpose: Distinguishing different types of implants and assessing the position and size of implants by radiologic exam after orbital wall reconstruction is important in determining the surgery outcome and forecasting prognosis. We observed time-dependent density changes in three types of implants (porous polyethylene, resorbing plate and titanium mesh plate) by performing facial bone CT after orbital wall reconstructions. Methods: A total of 32 patients, who had underwent orbital wall fracture surgery from October 2006 to March 2009 and received facial bone CT as outpatients at 1 postoperative year were included in the study. Follow-up facial bone CT was performed on the patients pre- operatively, 1 month post-operatively, and 1 year post-operatively to observe the status of the orbital implants. Medpor $^{(R)}$ (Porex Surgical, Inc., Newnan, Ga.) was used as porous polyethylene and followed-up in 14 cases; for resorbing plate, Synthes mesh plate (Synthes, Oberdorf, Switzerland) was used in the reconstruction, and followed-up in 11 cases; and titanium mesh plate usage was followed-up in 7 cases. Computed tomographic scan (CT) and water's view were done for radiography, and hounsfield unit (HU) was used to compare density of those facial bone CT. Wilcoxon signed rank test was applied to statistically verify measurement difference in each group of hounsfield units. Results: Facial bone CT examination performed in 1 month post-operative showed that the density of porous polyethylene, resorbing plate and titanium mesh plate were -42.07, 105.67 and 539.48 on average, respectively. Among the three types of implants, titanium mesh plate showed the highest density due to its radiopaque feature. Following up the density of three types of implants in CT during 1 year after the orbital wall fracture surgery, the density of porous polyethylene increased in 10.52 House Field Units and the resorbing plate was decreased in 26.87 HouseField Units. There were no significant differences between densities in 1 month post-operatively and 1 year post-operatively in each group ($p{\geq}0.05$). Conclusion: We performed facial bone CT on patients with orbital fractures during follow-up period, distinguishing the types of implants by the different concentration of implant density, and the densities showed little change even at 1 year post-operative. To observe how implant densities change in facial bone CT, further studies with longer follow-up periods should be carried out.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.223-227
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• 1998

The objectives of this study were to find the sprouting condition and to establish the optimum production methods of plug seedlings in yacon (Polymnia sonchifolia Poepp. & Endl.). The sprouting ratio was greatest at $30\pm 1^{\circ}C$ at 20 days after planting. Crowns with single buds were more effective than those with two or more buds for sprouting, which might be due to the apical dominance. Planting the shoots separated from crown after sprouting in the single- and double-layer polyethylene-covered greenhouses reduced seedling period with 25% and 50%, respectively. Planting the shoots after sprouting was more effective than planting the crown buds. Double-layer polyethylene-covered green-house was good for plug seedling production than open field or single-layer polyethylene-covered greenhouse. The bed soils composed of clay loam : compost or sand : compost (1:l=v:v) were more effective to produce plug seedlings than only clay loam, sand or compost. Seedlings could be produced at 30 days after planting in our studies.