• Korean Journal of Materials Research
• /
• v.3 no.2
• /
• pp.166-174
• /
• 1993

Abstract The crack resistance of PSG(Phosphosilicate Glass) and PE-SiN(Plasma Enhanced CVD S${i_2}{N_4}$)films deposited on aluminium thin films on Si substrate was analyzed in this study. PSG was deposited by AP-CVD and PE- SiN by PE-CVD. All the films underwent repeated heat cycles at 45$0^{\circ}C$for 30 min. Crack formation and development were examined between each heat cycle. The crack behavior was found to be closely related to the stresses in the films. The stress induced by the difference in thermal expansion behavior between the passivation layers and underlying aluminum film may cause the crack. Crack resistance decreases as the thickness of PSG films increases due to the high tensile stress of the films. Phosphorus in the PSG films releases tensile stress and consequently the stress of the films tends to show compressive stress. As a result, crack resistance increased as the concentratin of P in the PSG films increased. Crack resistance in the PE-SiN films also increased with compressive stress. An experimental model to predict crack generation in the PSG and PE-SiN films during heat cycle was suggested.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.8
• /
• pp.1284-1290
• /
• 2007

This study was conducted to investigate the antibacterial activity and shelf-life extension effect of iceberg lettuce packed in BN/PE film. The BN/PE film has a strong microbial suppression effect on pathogenic bacteria such as Escherichia coli, Salmonella enteritidis, and S. typhimurium. The number of psychrophiles and mesophiles during 5 days of cold storage of fresh-cut iceberg lettuce at $10^{\circ}C$ packaged in BN/PE film was strictly suppressed in comparison with other tested films (OPP, PE, and PET film). When fresh processed iceberg lettuce was processed and stored under the current conditions, the shelf-life of the product was longer than 5 days in the BN/PE film package, whereas the shelf-life when using the other films tested, PE, OPP and PET, was no longer than 3-4 days. The decay rates of the iceberg lettuce packed in the BN/PE film was maintained at $29.8{\pm}2.1%$ on the 5th day of preservation. The samples packed in BN/PE film maintained an excellent visual quality during the 3 days of storage without significant differences in comparison with the initial visual quality. No browning was observed in the samples packed in BN/PE film for up to 3 days. The texture of shredded iceberg lettuce packaged in BN/PE film remained unchanged up to 3 days, and then a moderate decrease in texture was observed after 4 days of storage. In addition, the overall acceptability of fresh-cut iceberg lettuce packaged in BN/PE film did not change for up to 3 days, whereas the samples packaged in the other films were inedible by 3 days of storage. In conclusion, the shelf-life of fresh-cut iceberg lettuce packaged in the BN/PE film was extended to more than 5 days at $10^{\circ}C$, whereas that in the other films was 2 days at $10^{\circ}C$. Therefore, the shelf-life extension effect of the fresh-cut iceberg lettuce in BN/PE film packaging was very effective compared with the other films tested.

• The korean journal of orthodontics
• /
• v.36 no.6
• /
• pp.451-464
• /
• 2006

The purpose of this study was to search for an appropriate method of coating $TiO_2$ on orthodontic appliances. $TiO_2$ thin films were deposited on orthodontic wires and brackets using sol-gel, CVD (Chemical Vapor Deposition) and PE-CVD (Plasma Enhanced-CVD) methods. The roughness of $TiO_2$-coated surfaces was investigated via scanning electron microscope (SEM) and adhesive strength of $TiO_2$ thin films was measured by adhesive tape pull test. Methylene blue degradation test was carried out to evaluate the photocatalytic activity of $TiO_2$ and the corrosion resistance of $TiO_2$ thin films against fluoride solution was also analyzed by observing the surfaces of $TiO_2$-coated wires and brackets via SEM after immersion in sodium fluoride solution. Through the comparison of properties and photocatalytic activity of $TiO_2$ thin films according to the coating methods, the following results were obtained. Smoother surfaces of $TiO_2$ thin films were generated by CVD or PE-CVD methods than through the sol-gel method or the control. Adhesive strength of the $TiO_2$ thin films was highest in PE-CVD and gradually became lower in the order of CVD, then the sol-gel method. Photocatalytic activity of $TiO_2$ thin films on methylene blue was the highest in PE-CVD and gradually became lower in the order of CVD, then the sol-gel method. Corrosion resistance of $TiO_2$ thin films against fluoride solution was stronger in CVD and PE-CVD methods than in the sol-gel method. The results of this study suggest that the CVD or PE-CVD methods is more appropriate than the sol-gel method for $TiO_2$ coating on orthodontic wires and brackets.

• Preventive Nutrition and Food Science
• /
• v.6 no.2
• /
• pp.112-116
• /
• 2001

Oxidized potato starch/polyethylene (PE) cast films were prepared with different percentages of linear low density PE (LLDPE), oxidized potato starch and prooxidant. For the determination of biodegradability of the films, lignocellulose-degrading Streptomyces viridosporus T7A (ATCC 39115) was used. Films were chemically disinfected and incubated with S. viridosporus by shaking at 100 rpm at 37$^{\circ}C$ for eight weeks. Hydroxyl indices of the films by Fourier-Transform Infrared Spectroscopy, mechanical Properties of the films by Instron and film morphology by scanning electron microscope (SEM) were measured. The hydroxyl index of the film containing the oxidized potato starch incubated with S. viridosporus T7A was higher than that of the corresponding control. All the films containing 5% and 10% oxidized starch showed a decrease of tensile strength on the films after incubation when the corresponding uninoculated film was compared. In the oxidized starch/PE film incubated with S. viridosporus T7A, partial destruction of starch and PE was examined by SEM.

• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1298-1305
• /
• 2000

Potato starches were crosslinked with 0.1, 0.5, 1.0, and 2.0% epichlorohydrin. Starch/polyethylene(PE) cast films were prepared to contain 5% of the crosslinked potato starch. Mechanical properties and degradability of these films were measured and compared to those of the films containing native potato starch. Mechanical strength of the films containing crosslinked potato starch was higher than that of the film containing native starch. Thermal degradability measured by a FT-IR and an Instron showed that crosslinked starch/PE films degraded faster than native starch/PE films. Biodegradability of the starch/PE films was accelerated by the addition of crosslinked starch to the PE films.

• Journal of Bio-Environment Control
• /
• v.25 no.2
• /
• pp.111-117
• /
• 2016

The objective of this study was to analyze the microclimate and the growth of tomato and lettuce in the greenhouses covered with spectrum conversion films using different phosphor particles sizes. Two spectrum conversion films using phosphor particles larger than $10{\mu}m$ (Micro-film) and smaller than 500 nm (Nano-film) in radius, and poly-ethylene (PE) film were used in double-layered greenhouses as outer coverings. PE films were used as inner coverings in all the greenhouses. Thickness of the films for inner and outer coverings was 0.06 mm. Tensile strength, elongation, and tearing resistance of the Micro- and Nano-films were not different from those of the PE film. Transmittances at a wavelength of 300-1100 nm were a little higher at the Micro-film and lower at the Nano-film than that of the PE film, respectively. Air temperatures at the Micro- and Nano-films were over $2^{\circ}C$ higher than at the PE film, but no significant difference was observed between the two light conversion films. The soil temperature at the Nano-film was $1.5^{\circ}C$ and $3^{\circ}C$ higher than at the Micro- and PE films, respectively. The yields of tomato at the Micro- and Nano-films were 12% and 14% higher than at the PE film, but no significant difference was observed between the two spectrum conversion films. The total soluble solid showed no significant differences among all the films. The yields of lettuces at the Micro- and Nano-films were 27% and 59% higher than at the PE film. Hunter's red (a) value of the lettuce leaf was the highest at the Nano-film. In this experiment, tomatoes requiring high irradiation were better at the Nano film, while lettuce requiring low irradiation better at the Micro film.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.52-52
• /
• 2022

Recently, PE (polyethylene) film has been used increasingly in com cultivation. However, PE films often cause soil and environment contamination. In order to reduce this problem, many researches have been carrying out studies on biodegradable films (BF) that are easily decomposed by soil microorganisms. Therefore, this study was conducted to determine which BF is optimal for growth and yield of com crops while also having the highest rates of film decomposition. BFs Farmsbio (Farm Hannong), Heulgro Film (Sejin Bio), Vonto Film (Eco-Hansung) as well as a selected PE film were used in this study. For the control, we used crops grown without any kind of mulching. Experimental fields were fertilized according to conventional cultivation methods, tilled, and then covered by either BF or PE. After 1 week, com (cv. MIBECK2ho) at the 3-leaf stage (16 days after seeding) was transplanted. Plant height was measured at 18 and 32 days after transplanting and heading stages. Yield components and yield were also measured at harvest. In addition, pH, EC, and decomposition and light transmittance levels of films were investigated during the experimental period. Daily average temperature, relative humidity and organic matter in soils were also measured during the experimental period. There was no significant difference in plant height, heading date, and silking between crops with BFs and PE, but the crops grown with BFs and PE films reached higher growth parameters in a shorter amount of time than the crops in the non-mulching control. Additionally, there were no significant differences in yield components such as length of ears, ear width, ear weight, and yield in crops that were grown using films or crops in the control plot. Light transmittance and decomposition levels of films generally increased with time after transplanting, and was highest in the Heulgro film than other BFs. Soil pH and organic matter in crops using BFs and PE films were significantly higher than in the control plot at 99 and 113 days after transplanting. In general, the EC contents in the control plot was lower than in crops using BFs and PE films. The average daily moisture in soil was higher when BFs and PE films were used than in the control plot. However, the daily average soil temperature was higher in crops using BFs and PE films than in the control plots at the beginning of the experimental period, but there was no consistent difference in soil temperature towards the later part of the experimental period. Therefore, the BFs used in this study were shown to be helpful without causing negative impacts on the growth and yield of com.

• Journal of Bio-Environment Control
• /
• v.24 no.4
• /
• pp.326-332
• /
• 2015

The effect of biodegradable mulching film on the growth and development of garlic were investigated in order to develop eco-friendly weed control techniques. The treatments included biodegradable film (Bio-De) and black (Black-PE), green (Green-PE), transparent (Trans-PE) polyethylene mulching films. Non-mulched, bare soil (Non-mulching) was used as a control. Light transmittance value among tested mulching films was the highest in Trans-PE (86.1%) followed by Bio-DE and Green-PE, and the lowest value was observed for the Black-PE (1.1%). All mulching films without exclusion elevated soil temperature, especially Trans-PE and Bio-DE compared to bare soil. Plant height and mean bulb weight were increased due to mulching films with the highest values observed for Trans-PE and Bio-DE treatments. After seven months of field application there were no significant degradation signs on PE plastic films, whereas it was easy to see horizontal cracks on the Bio-DE film surface after five month of usage.

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

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.69 no.1
• /
• pp.34-48
• /
• 2024

The objective of this study was to evaluate the safety of biodegradable mulching films in soybean (Glycine max) cultivation by measuring their effects on crop growth and yield, film decomposition and soil chemical and physical properties. In 2022 and 2023, plant height, branch number, chlorophyll contents, yield components, and yield of soybean did not vary significantly in areas using PE films and biodegradable mulching films. The light transmission rate of the biodegradable mulching films ranged from 6.4 to 15.8% when measured 112 days after soybean transplanting, and was higher, on average, in 2023 than in 2022. In both years, degradation of the biodegradable mulching films began 20 days after soybean transplantation and increased over time. In addition, remains of biodegradable mulching films were present in fields at soybean harvest and remained until 50 days after harvest. Decomposition rates of the biodegradable mulching films at 112 days after soybean transplanting ranged from 9.8 to 26.7% in 2022 and 13 to 36% in 2023. Although soil pH and EC varied based on the year and timing of measurements, there was no significant difference between areas that used biodegradable mulching films and PE films. Soil organic matter, nitrate and exchangeable cation contents such as Ca, Mg, and K were not significantly different in areas that used both PE films and biodegradable films. However, significantly higher levels of available phosphoric acid content were measured in areas that used biodegradable mulch films E, S, and T. Regardless of which films were used, there were no significant differences in the soil's physical properties. In 2022 and 2023, there was no difference between areas that used biodegradable mulch films and PE films. However, soil temperature in mulched areas was 2℃ higher and soil moisture was 5-15% higher than in non-mulched areas. Barley growth was not affected by being planted in soil that had been used for soybean cultivation with biodegradable films. Therefore, the biodegradable mulch films used in this study can be used without negatively affecting the growth, yield, and soil environment of soybeans.