• Journal of Korean Society of Forest Science
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• v.109 no.1
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• pp.31-40
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• 2020

This study aimed to investigate the effects of climate change on the survival and growth performance of Pinus densiflora and Larix kaempferi seedlings using open-field experimental warming and precipitation manipulation. We measured the survival rate, root-collar diameter, and height, and then calculated the seedling quality index (SQI) of 2-year-old seedlings under 6 treatments [2 temperatures (TC: Control; TW: Warming) × 3 precipitation manipulations (PC: Control; PD: Decreased; PI: Increased)] and performed a two-way ANOVA to test for differences.The air temperature of the warming plots was 3℃ higher than that of the control plots, while the precipitation manipulation plots received ±40% of the precipitation received by the control plots. Temperature and precipitation treatments did not significantly affect the survival rate of P. densiflora; however, the SQI of P. densiflora decreased with increasing precipitation. In contrast, the mortality rate of L. kaempferi increased with increasing temperature and decreasing precipitation. Furthermore, in L. kaempferi, TC × PI treatment resulted in the lowest SQI with a significant interaction effect observed between the two factors. In summary, low seedling production and quality should be expected in P. densiflora as precipitation increases and in L. kaempferi as temperature increases or precipitation decreases. These results indicate species-specific sensitivities to climate change of two plant species at the nursery stage. With the occurrence of global warming, the frequencies of drought and heavy rainfall events are increased, and this could affect the survival and seedling quality of tree species. Therefore, it is necessary to improve nursery techniques by establishing new adaptation strategies based on species-specific growth performance responses.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.155-162
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• 2004

Different adhesives(CF-clear, arabic gum, cethylmethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxy propyl cellulose, methyl cellulose) and particulate matters(bentonite, kaolin, calcium carbonate, peatmoss, talcum, vermiculite, zeolite, calcium hydroxide, plaster, calcium phosphate, vermiculite + calcium carbonate, vermiculite + kaolin, vermiculite + talcum) were evaluated by coating index method. According to the weight of single coated seeds, CF-clear and polyvinyl alcohol appeared to be the best coating adhesives for red clover and tall fescue seeds. Both vermiculite and vermiculite + talc(l : 1) for red clover, and vermiculite + talc(l : 1) for tall fescue appeared to be the best particulate matter(P < 0.01). Percent friability showed excellent results for the arabic gum, CF-clear, and polyvinyl alcohol when compared to others(p < 0.01). The coating index showed high with vermiculite and vermiculite + talc(l : 1) in coating red clover seed, and talc, vermiculite, and vermiculite + talc showed good coating index in coating tall fescue seed.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.220-231
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• 2002

The fish fauna and Community were surveyed from April 2000 to September 2001 at 23 stations in the nam river, the first tributary located to the lower reach of the Nakdong River system. During the study period, 39 species belonging to 29 genera and 11 families were collected. Of which 14 species are endemic species or subspecies in Korea. Introduced species from other river system, O. bidens had not been collected at all after the report of Yang (1973) but many individuals were captured at main stream and tributary in this survey. Introduced species from abroad M. salmoides increased at most of stations. Dominant species in main stream were Z. platypus, O. bidens and H. labeo. On the contrary, Z. temmincki, Z. platypus and S. gracilis majimae dominated the tributaries. Diversity indices of main stream and tributaries were 0,979 and 0.966 respectively. St. 3 of main stream and St.1 and 16 of tributaries had high diversity indices (1.05, 0.962, 0.956) and lower dominant indices (0.102, 0.369, 0.200). As a whole, dominant index was 0.160, diversity index 1.044 and evenness index 0.656. It indicated that the community structure of this river was stable and diverse relatively.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.34-39
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• 2023

Growth modeling in plant factories can not only control stable production and yield, but also control environmental conditions by considering the relationship between environmental factors and plant growth rate. In this study, using the expolinear function, we modeled perilla [Perilla frutescens (L.) Britt.] cultivated in a plant factory. Perilla growth was investigated 12 times until flower bud differentiation occurred after planting under light intensity, photoperiod, and the ratio of mixed light conditions of 130 μmol·m^-2·s^-1, 12/12 h, red:green:blue (7:1:2), respectively. Additionally, modeling was performed to predict dry and fresh weights using the expolinear function. Fresh and dry weights were strongly positively correlated (r = 0.996). Except for dry weight, fresh weight showed a high positive correlation with leaf area, followed by plant height, number of leaves, number of nodes, leaf length, and leaf width. When the number of days after transplanting, leaf area, and plant height were used as independent variables for growth prediction, leaf area was found to be an appropriate independent variable for growth prediction. However, additional destructive or non-destructive methods for predicting growth should be considered. In this study, we created a growth model formula to predict perilla growth in plant factories.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.68-77
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• 2006

This study was peformed to document the association between nutrient intakes, body mass index (BMI), waist/hip ratio (WHR), and a major risk factor for chronic diseases. A three-day dietary intake survey, using a 24 hour recall method, was obtained from 187 subjects aged 46 to 84 (mean age 65.3) living in Wando island area. The average daily mean energy intakes were 1869.0 kcal for male and 1943.9 kcal for female, respectively. Daily intakes of protein for male and female were 28.0 and 30.4 g, and those of fat were 31.5 and 28.51 g, respectively Carbohydrate dependency was decreased with age. Protein dependency was increased with age. The mean intakes of energy, protein, Vit. A, Vit. D, Vit. E, Ca, Zn did not meet Korean RDA for elderly. The level of serum triglyceride was higher in males than in females and showed the tendency to increase with age in both sexes, whereas HDL-cholesterol tended to decrease with age in both sexes. The levels of serum total-cholesterol and LDL-cholesterol were significantly higher in males than in females, particularly in the age of $46\~59$ (p<0.05). The level of atherogenic index (AI) was significantly higher in females than in males, particularly in the age of 80 and over (p<0.05) Based on these results, it is evident that people in island area did not consume enough nutrient. Specially, dietary intake of protein was not adequate. This study implies that triglyceride, total-cholesterol, LDL-cholesterol, AI were increased with increasing age, BMI and WHR.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.559-572
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• 2021

A survey was conducted to analyze water masses and spatial distributions of phytoplankton communities at 15 stations on the surface and chlorophyll a maximum layers (CML) in the western South Sea of Korea from September 8 to 9, 2021. As a result, water masses were classified into Coastal Waters (CW) with relatively low salinity, the Tsushima Warm Current (TWC) with high water temperature and high salinity, and mixed waters (MW) showing a mixture of these two water masses. Turbidity showed high concentration in both the surface and CML. The chlorophyll a concentration was as low as 0.90±0.43 ㎍ L^-1 in the surface, more than 1.1 ㎍ L^-1 in CW, around 1.0 ㎍ L^-1 in MW, and less than 0.5 ㎍ L^-1 in the TWC. CML was 1.64±0.54 ㎍ L^-1. Regarding species composition of phytoplankton communities, there were 57 species in 31 genera(diatoms, 57.8%; dinoflagellates, 35.1%; and other phytoflagellates, 7.1%). The phytoplankton standing crop had 4.6±7.6 cells mL^-1 in the surface, more than 30 cells mL^-1 in the CW, 2-5 cells mL^-1 in the MW, and less than 2 cells mL^-1 in the TWC. CML was slightly higher than the surface with a variation of 5.7±8.4 cells mL^-1. Dominant species were found to be Rhizosolenia flagilissima f. flagilissima, Skeletonema costatum-ls, and Nitzschia sp./ small size in the surface. For the CML Rh. flagilisima f. flagilissima showed a dominance of 12.0%. For the surface, the diversity variation was 2.36±0.40, which was high for TWC but low for MW. For CML, the diversity variation was 2.29±0.52, which was slightly lower than that of the surface. The dominance in the surface was 0.50±0.15, with a fluctuation range of more than 0.5 in MW and less than 0.5 in the TWC, which was different from the diversity. According to correlation analysis and principal component analysis (PCA), the presence of phytoplankton standing crops was high in CW but low in MW and TWC. That is, phytoplankton communities in early autumn were strongly affected by the expansion and mixing of water masses in western South Sea.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.707-715
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• 2011

Objectives : The objective of this study was to assess a level of oral health related quality of life(OHRQoL) for rural communities elderly and to determine the association between OHRQoL and socio-economic position. Methods : The study population was elderly(60+year-old) residents of PyeongChang county, Jeongseon county, Yeongwol county, Gangwon province. A total of 171 people were invited to participate. Oral health related quality of life was measured using the GOHAI. The data were analyzed with Mann-Whitney U test or Kruskal-Wallis test and to assess socio-economic inequalities in OHRQoL(GOHAI), we used multi-variable logistic regression models. We used models adjusting for age, sex, family status factors(Model I) and compared them to models additionally adjusting for stress level(Model II). Results : There were significant differences in lower score of GOHAI at lower age group and live alone group. And we found that lower SES was significantly associated with lower score of OHRQoL. Social gradient in the score of OHRQoL persisted when adjusted for age, sex, family status, stress level. Conclusions : We recommend that oral health promotion program should be developed after due consideration SES for rural communities elderly because OHRQoL of rural communities elderly was low and association between SES and OHRQoL for rural communities elderly.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.481-489
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• 1996

D,L-lactide (2-LA) was copolymerized with ${\beta}$-methyl-${\delta}$-valerolactone (MVL) using tetraphenyltin as a catalyst and the properties of the copolymers were investigated. The composition of the repeating unit of lactic acid in the copolymers was higher than that in the monomer feeds. The composition of the lactic acid unit in the copolymers decreased with increasing copolymerization time. The yield and the molecular weight of the copolymer increased with increasing 2-LA in the feed composition. These results suggest that the reactivity of 2-LA is larger than that of MVL. The number average molecular weight was in the range of 54,000 to 63,000 and the polydispersity index was in the range of 1.7 to 2.1. The copolymers did not show melting point, but glass transition temperature. The degradable tendency of the copolymers with lipase was almost equal to that of L-lactide-MVL copolymer.

• Journal of Korean Dental Hygiene Science
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• v.5 no.2
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• pp.145-153
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• 2022

Background: The purpose of this study was to analyze the association between the Geriatric Oral Health Assessment Index (GOHAI) and Quality of Life (QoL) between urban and rural residents in Koreausing data from the Korea Longitudinal Study of Aging (KLoSA). Methods: This study was analyzed using the SPSS 20.0 program (IBM SPSS Statistics), and a t-test was performed for difference between GOHAI and QoL, and a multiple regression analysis was used for association between the independent and dependent variables with confounding variables corrected. The statistical significance was p<0.05. Results: Urban residents' average QoL was statistically significantly higher rural residents'(Table 1, p>0.05). For subjects under the age of 65, the QoL increased by 0.30 points for urban residents and 0.39 points for rural residents according to GOHAI increased by one unit (Table 2, p>0.05). Also, for subjects aged 65 years or older, the QoL increased by 0.42 points for urban residents and 0.61 points for rural residents according to the GOHAI, increasing by one unit (Table 3, p>0.05). Conclusion: Through the results of this study, the quality of life of rural residents was lower than that of urban residents. The GOHAI had a stronger impact on QoL among rural residents than in urban areas. In order to address the disparity in QoL between urban and rural residents, it was believed that policies aimed at improving oral health for rural residents should b etaken in to account.

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.8-14
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• 2024

Austenitic stainless steel 316L has been used a lot of applications because of its high corrosion resistance and formability. In addition, copper brazing is employed to create complex shape of 316L stainless steel for various engineering parts. In such system, copper-based filler metals make galvanic cell at metal/filler metal interface, and it accelerates corrosion of stainless steel. Furthermore, Cu-rich region formed by diffused copper in austenitic stainless steel can promote a pitting corrosion. In this study, we used an ammonia (NH₃) gas to nitride the 316L stainless steel for improving the corrosion resistance. The thickness of the nitride (nitrogen high) layer increased with the treatment temperature, and the surface hardness also increased. The potentiodynamic polarization test showed the improvement of corrosion resistance of 316L stainless steel by enhancing the passivation on nitride layer. However, in case of high temperature nitriding, a chromium nitride was formed and its fraction increased, so that the corrosion resistance was decreased compared to the intact 316L stainless steel.