• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.231-238
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• 2006

The physical properties of seven perlites different in particle size distribution were investigated to develop perlite bag culture in Korea. Particle sizes of 1.0-2.8mm and larger than 2.8 mm were rather evenly distributed in S-1 (1.2-5 mm), S-2 (0.15-5 mm) and S-5 (parat No.1). Larger particles were less in S-3 (1-3 mm), S-4 (Parat No.2), S-6 (OTAVI) and S-7 (Agroperl B-3). S-4, S-6 and S-7 contained lots of particles less than 1 mm in size. Total porosity was similar among substrates with the value of $59{\sim}62%$. Container capacity was between 35-40% regardless of substrates except in S-2 with 27.7%. Water content, which was about 60% at 0 kPa, was decreased sharply at 4.90 kPa regardless of substrates, which meant the easily available water was plenty in any kind of perlite tested. Substrates, S-1, S-2 and S-3 with different particle size distribution, were investigated to evaluate for perlite bag culture. Six tomatoes (Licopersicon esculentum Mill. cv. Rokkusanmaru) were planted in a perlite bag of 40 liters with the dimension of 120cm in length and 34cm in width. The amount of nutrient solution supplied and its drainage dependent on daily integrated radiation didn't show any regular trend during the growth. Roots in the bag were distributed evenly in S-1 and S-2 than in S-3. Plant grown in S-1 showed the highest total and marketable yield of 8,628 and 7,759 kg/10a, respectively. The number of small size fruits and malformed fruits were more in S-3. Consequently, S-1 with the particle size distribution of 1.2-5 mm is suggested as desirable substrate for perlite bag culture.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.345-354
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• 2020

The purpose of this study was to investigate the effects of soil amendment treatments, such as hydroball, and active carbon, and planting Pennisetum alopecuroides for reducing calcium chloride (CaCl₂) of soil leachate and the growth of Pennisetum alopecuroides. The experiment planted Pennisetum alopecuroides in a plastic pot with a diameter of 10 cm and a height of 9 cm in a greenhouse April-October 2018. The experimental group comprised six treatments, including Non-treatment (Cont.), Hydroball (H), Active carbon (AC), planting Pennisetum alopecuroides (P), hydroball + planting Pennisetum alopecuroides (H + P), and active carbon + planting Pennisetum alopecuroides (AC + P). The dissolution of the CaCl₂ concentration 200ml of 10g/L was irrigated once every two weeks. We measured the growth (plant height, leaf length, leaf width, number of leaves), EC, pH, and exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) according to the high concentration of CaCl₂ in the plant and soil leachate. In a treatment with the 'hydroball' amendment, the soil leachate electrical conductivity (EC), and the cation exchangeable were decreased more than those of the control, while the growth of Pennisetum alopecuroides relative growth rate(RGR) increased. Overall, application with the hydroball amendment added the planting of Pennisetum alopecuroides improved the salt reduction effect more than the control group. These results indicate that the application of the soil amendment agent hydroball was suitable soil amendments in accordance with the high concentration of calcium chloride (CaCl₂). Also, Planting Pennisetum alopecuroides is expected to be appropriate for salt-tolerant plant for soil affected by deicing salt agents.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.198-206
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• 2015

Purpose: We aimed to investigate the effect of combined various microgrooves and thermal oxidation on the titanium (Ti) and to evaluate various in vitro responses of human periodontal ligament cells (PLCs). Materials and methods: Grade II titanium disks were fabricated. Microgrooves were applied on titanium discs to have $0/0{{\mu}m}$, $15/3.5{{\mu}m}$, $30/10{{\mu}m}$, and $60/10{{\mu}m}$ of respective width/depth by photolithography. Thermal oxidation was performed on the microgrooves of Ti substrata for 3 h at $700^{\circ}C$ in air. The experiments were divided into 3 groups: control group (ST), thermal oxidation group (ST/TO), and combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO). Surface characterization was performed by field-emission scanning microscopy. Cell adhesion, osteoblastic differentiation, and mineralization were analyzed using the bromodeoxyurdine (BrdU), Alkaline phosphatase (ALP) activity, and extracellular calcium deposition assays, respectively. Statistical analysis was performed using the oneway analysis of variance and Pearson's bivariate correlation analysis (SPSS Version 17.0). Results: In general, the combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO) showed significantly higher levels compared with the control (ST) or thermal oxidation (ST-TO) groups in the BrdU expression, ALP activity, and extracellular calcium deposition. Gr60-TO group induced highest levels of cell adhesion and osteoblastic differentiation. Conclusion: Within the limitation of this study, we conclude that the Ti surface treatment using combined microgrooves and thermal oxidation is highly effective in inducing the cell adhesion andosteoblastic differentiation. The propose surface is also expected to be effective in inducing rapid and strong osseointegration of Ti oral implants.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.42-48
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• 2016

Angelica gigas, belonging family Apiaceae, is a perennial and famous medical plant growing in Korea, Japan, and China. The aims of this study was to analyze the growth and accumulated Decursin and its precursor Decursinol angelate of A.gigas grown under fluorescent lamp and LED. A. gigas 'Manchu' were sowed and managed for seedlings stage in a glass house for 4 weeks. One hundred twenty seedlings with 3 true leafs were transplanted at an ebb & flow system with fluorescent lamp and LED [red: peak wavelength 660nm, blue: peak wavelength 455 nm, white = 3:2:4 ratio] irradiated at $180{\pm}7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at the top of plant canopy for 5 weeks. The number of leaves increased by 13.5% in the LED treatment, though it is not statistically significant. Leaf length/width ratio of A. gigas grown under the fluorescent lamps was 24% bigger than the LED treatment and also the stem was 13% larger. Maximum root length was similar to both groups. Fresh weight and dry weight of shoots grown under the LED increased by 50% and 42% and the both weights of roots increased by 125% and 45%, respectively. The contents of Decursin and Decursinol angelate grown under the florescent lamps were larger than LED by 188% and 27% in shoot and 78% and 8% in root. The contents of Decursin and Decursinol angelate per plant grown under LED and florescent lamps were 132mg and 122mg. In conclusion, functional materials in A. gigas were increased by florescent light and its growth was promoted by LEDs light.

• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.43-48
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• 2017

This experiment was conducted to test the suitability of various organic materials in order to reduce the use dependence of peatmoss as a soil pH regulator and to examine the effect of soil organic matter supply. A 2-year old northern-highbush blueberry (Vaccinium corymbosum L.) 'Duke' plants were planted in the field at $2.0m{\times}2.5m$ spacing in spring. Before planting, organic materials were incorporated into the soil including the planting hole at 20 liter per plant, as the following mixtures: peatmoss only (20 L), peatmoss (10 L) + pine needle (10 L, PN), peatmoss (10 L) + rice hull (10 L, RH), and peatmoss (10 L) + sawdust (10 L, SD). The pH of organic materials was lowest in peatmoss (pH 4.3), followed by PN (pH 4.8), SD (pH 5.7) and RH (pH 7.8). Soil pH measured right after planting ranged from 5.3 to 5.9 and was lower in PM only and PM + PN than PM + RH and SD treatments. In the third year, the pH lowered to the range of 4.2 to 4.5, with PM and PM + PN still maintaining lower values. The early growth was good in the mixed treatment of PM and PN, and the plant height and width and the number of new shoots were good in the PM treatment. Soil water content was maintained highest in PM + PN, followed by PM, PM + SD and PM + RH. Vegetative growth was maintained better in PM and PM + PN, and the number of flower cluster and yield were also slightly higher in those treatments while mean fruit weight was similar among all treatments. Fruit quality indices such as total soluble solids, titratable acidity and firmness were not affected.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.275-283
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• 2007

This study was carried out to: (1) analyze structural stability of representative rain-sheltering greenhouses for large-grain grapevine cultivation with widths of 3.6 m and 5 m in case of using the existing pipe for agriculture; (2) present the optimum specification of pipes in the greenhouse with a width of 5 m under the condition of using the pipe of which ultimate strength has been above $400N{\cdot}mm^{-2}$; (3) evaluate stability and also present the optimum specification of pipes as eaves height was augmented. The above analyses were done for greenhouses with roof vents and also with a main-column interval of 3 m and a rafter interval of 60 cm. First, the existing 3.6 m greenhouse with a rafter of ${\Phi}25.4{\times}1.5t@600$ was stable far a snow-depth of 35 cm but unstable for a wind velocity of $35m{\cdot}s^{-1}$. Meanwhile the existing 5 m greenhouse with the same rafter was not stable for a wind velocity of $335m{\cdot}s^{-1}$ as well as a snow-depth of 35 cm. This meant that existing greenhouses had to be reinforced to secure stability. Second, the specification of pipes, especially rafter, could be classified as two cases. One had a structural stability at a safe wind velocity of $35m{\cdot}s^{-1}$ and a safe snow-depth of 40 cm for which stability the rafter had to be ${\Phi}31.8{\times}1.5t@600$, and the other had a stability at $30m{\cdot}s^{-1}-35cm$ at the specification of rafter ${\Phi}25.4{\times}1.5t@600$. Finally, eaves height had a significant effect on safe wind velocity. But it had little influence on safe snow-depth. The results showed that the specification of side-wall pipes had to be reinforced for the safe side velocity accord-ing to the increment of eaves height and similarly the specification of fore-end post far the safe fore-end velocity.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.148-157
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• 2014

The purpose of this study was to investigate greenhouse maintenance by farms by looking into greenhouses across the nation for greenhouse specification, disaster-resistance greenhouse construction, types and degree of damage due to natural disasters, pre-inspection in case of typhoon or heavy snow forecast, and fire-fighting facilities to prevent a fire. The findings were summarized as follows: as for greenhouse specification, the highest proportion of them were 90 m or longer both in single- and multi-span greenhouses in terms of length; 8 m or wider and 7.0~7.9 m in single- and multi-span greenhouses, respectively, in terms of width; 1.5~1.9 m and 2.0~2.9 m in single-and multi-span greenhouses, respectively, in terms of height; and 3.0~3.9 m and 6 m in single- and multi-span greenhouses, respectively, in terms of diameter. As for disaster-resistance greenhouses, farmers were reluctant to install such greenhouses. The low distribution of disaster-resistance greenhouses was attributed to the greenhouses built dependent on the old practice, the greenhouses already completed, and relatively high construction costs. As for damage by natural disasters, greenhouses were subject to more damage by typhoons than heavy snow. They mainly inspected the ceiling and side windows, entrances, and fixation bands for covering materials in case of typhoon forecast and the heating devices in case of heavy snow forecast. As for repair methods for greenhouse pipe corrosion, they preferred partial replacement to painting and did not use stiffeners for structures to prevent a natural disaster in most cases. As for the maintenance of greenhouse covering materials, most farmers inspected their sealing property but did not clean the coverings for light transmission. The destruction of structural materials can be prevented by eliminating greenhouse covering materials during a typhoon, but they were not able to do so because of the covering material replacement costs and the crops they were growing. The study also examined whether greenhouse farms had fire-fighting facilities to prevent a fire and found that they lacked the perception of greenhouse fire prevention to a great degree.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.424-431
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• 2017

This study was conducted to set the optimum nutrient solution concentration by growth stage for new strawberry cultivars 'Berrystar' and 'Jukhyang'(Fragaria ${\times}$ ananassa Duch. cvs. 'Berrystar', 'Jukhyang') grown through hydroponics to improve the quality and yield. Three different EC levels were applied to the nutrient solution. The treatment levels were 0.7, 1.0 and 1.3 times higher than the nutrient concentration standard for 'Seolhyang' based on the 'Manual for strawberry cultivation' of Rural Development Administration. Based on the results, there were no significant differences in growth of 'Berrystar' by EC level. 'Jukhyang' showed the most vigorous growth grown in 1.3 times higher nutrient concentration. While the growth of 'Berrystar' and 'Jukhyang' grown in higher EC level has leaves with more chlorophyll concentration. However the quantum yield of leaves was not affected by the treatments. On the treatment with 1.3 times higher EC level, the weight, length, width and firmness of 'Berrystar' and 'Jukhyang' were significantly high. The sugar contents of the harvest analyzed by HPLC did not differed particularly, but the percentage composition of reducing sugar and non-reducing sugar were presented differently depending on the treatments. Marketable fruit yield increased as nutrient concentration increases. However, there were no large differences by treatments. Meanwhile, 'Jukhyang' showed significant difference by nutrient concentration and had the largest yield for a treatment grown in 1.3 times higher EC level. Based on these results, it is recommended to provide the same nutrient solution concentration level to the nutrient concentration standard of 'Seolhyang' for 'Berrystar', and the 1.3 times higher level for 'Jukhyang'.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.386-392
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• 2017

This study was conducted to examine the growth and phytochemical contents of spinach (Spinacia Oleracea L. 'Sushiro') as affected by different fluorescent lamps in a closed-type plant production system. Seeds were sown in a 128-cell plug tray filled in rockwool. The seedlings were transplanted into a DFT (deep floating technique) system with recycling nutrient solution (EC $1.5dS{\cdot}m^{-1}$ and pH 6.5) in a closed-type plant production system. The seedlings were grown under 3 types of fluorescent lamp, #S (NBFHF 32S8EX-D, CH LIGHTING Co. Ltd., China), #O (FHF32SSEX-D, Osram Co. Ltd., Germany), and #P (FLR32SS EX-D, Philips Co. Ltd., The Netherlands) at $150{\mu}mol{\cdot}m-2{\cdot}s^{-1}\;PPFD$ with a photoperiod of 14/10 (light/dark) hours. Plants were cultured under condition of $25{\pm}1^{\circ}C$ temperature and $60{\pm}10%$ relative humidity after transplanting. Thirty plants per each treatment were cultivated for $6^{th}$ week after transplanting. And growth and phytochemical contents were measured at $3^{rd}$ and $6^{th}$ week. At the $3^{rd}$ week after transplanting, the parameter values of plant height and leaf width were higher in the #O than the others. However, fresh and dry weights of root were the greatest in the #P. In addition, total phenolic concentration was the greatest in the #P. At $6^{th}$ week after transplanting, the #O had the greatest growth of spinach in the plant height and fresh and dry weights of shoot. The total phenolic contents significantly increased in the #O and showed significantly difference. However, there was no significant difference all treatments in antioxidant activity. Therefore, these results suggest that the #O was suitable for the growth and phytochemical accumulation of spinach in a closed-type plant production system.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.245-252
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• 2020

The purpose of this study was intended to recognize the importance of quality control (QC) in order to reduce exposure and improve image quality by comparing the center-point (CP) of according to hospital grade and the difference between X-ray field (XF) and light field (LF) in diagnostic digital X-ray devices. XF and LF size, CP were measured in 12 digital X-ray devices at 10 hospitals located in 00 metropolitan cities. Phantom was made in different width respectively, using 0.8 mm wire after attaching to the standardized graph paper on transparent plastic plate and marked as cross wire in the center of the phantom. After placing the phantom on the table of the digital X-ray device, the images were obtained by shooting it vertically each field of survey. All images were acquired under the same conditions of exposure at distance of 100cm between the focus-detector. XF and LF size, CP error were measured using the picture archiving communication system. data were expressed as mean with standard error and then analyzed using SPSS ver. 22.0. The difference in field between the XF and LF size was the smallest in clinic, followed by university hospitals, hospitals and general hospitals. Based on the university hospitals with the least CP error, there was a statistically significant difference in CP error between university hospitals and clinics (p=0.024). Group less than 36-month after QC had fewer statistical errors than 36-month group (0.26 vs. 0.88, p=0.036). The difference between the XF and LF size was the lowest in clinic and CP error was the lowest in university hospital. Moreover, hospitals with short period of time after QC have fewer CP error and it means that introduction of timely QC according to the QC items is essential.