• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.443-456
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• 2019

Objectives: Children are exposed to various environmental pollutants through contact with children's products. We investigated the KC mark, certification number, and contained substances labeled on children's products through market research and collected the toxicological data on these substances. Methods: The environmentally hazardous substances labeled on children's products (n=6576), including toys (n=2812), personal care products (n=2212), stationary/books (n=1333), and playground equipment (n=219) were examined. For the components that could be identified by CAS number, toxicological data on oral, inhalation, and dermal routes, cancer slope factor, and reference dose were collected. Results: Among the investigated products, KC marks or certification numbers were found for 4557 products (69.3%). Except for cosmetics and cleansers, the material information was labeled on most of the products. The frequency of labeling substance information in toys and stationary/books was low since this information could be omitted if KC certification was obtained. In the target products, 617 substances were identified by CAS number, and polypropylene, acrylonitrile butadiene styrene, and polyester were the most frequently displayed. Chronic toxicity data was found for only 32.4% of individual components, and information on toxicity through the dermal route was also highly limited. Conclusion: Our study suggested that labeling guidelines should be required to identify the environmentally hazardous substances contained in children's products. In addition, the toxicological data on many ingredients in children's products were insufficient. The data gap for toxicity data should be filled for future risk assessment.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.717-726
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• 2020

The physical characteristics of the major varieties of perilla were analyzed to use as basic data for the design of a high-quality, high-efficiency perilla cleaner and stone separator. Because the size, thousand-grain weight, angle of repose, angle of friction, bulk density and terminal velocity of perilla have significant differences according to the perilla variety, the different of characteristics by variety should be considered for performance improvement of a perilla cleaner and stone separator. Therefore the cleaner and stone separator using a sieve could be improved by the application of a detachable sieve or by using equipment such as a 2 - 3 stage sieve and regulating the slope. Moreover, because differences in the terminal velocity occur due to the differences in the size and thousand-grain weight according to the perilla variety, a blower with an adjustable fan speed was considered for the design of the improved cleaner. Additionally, it was shown that the length of perilla has the greatest correlation based on a comparison of the coefficients of the other characteristics. Accordingly, the length of perilla could be used as a major factor for the fine adjustment and parts replacement of the device. These results can be used as basic data for a high-quality, high-efficiency perilla cleaner and stone separator. In the future, the development of the machine and follow-up studies based on the basic data are needed to determine the optimized operating conditions and mechanism of action.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.229-240
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• 2020

Background: Genus Quercus is a successful group that has occupied the largest area of forest around the world including South Korea. The acorns are an important food source for both wild animals and humans. Although the reproductive characteristics of this genus are highly variable, it had been rarely studied in South Korea. Therefore, in Seoraksan and Odaesan National Parks (i) we measured the acorn production of Quercus mongolica, an overwhelmingly dominant species in South Korea, for 3 years (2017-2019), (ii) evaluated the spatial-temporal variation of acorn production, and (iii) analyzed the effects of oak- and site-related variables on the acorn production. Results: The annual acorn production of Q. mongolica increased 36 times from 1.2 g m-2 in 2017 to 43.2 g m-2 in 2018, and decreased to 16.7 g m-2 in 2019, resulting in an annual coefficient of variation of 104%. The coefficient of spatial variation was high and reached a maximum of 142%, and the tree size was the greatest influencing factor. That is, with an increase in tree size, acorn production increased significantly (2018 F = 16.3, p < 0.001; 2019 F = 8.2, p < 0.01). Elevation and slope also significantly affected the production in 2019. However, since elevation and tree size showed a positive correlation (r = 0.517, p < 0.001), the increase in acorn production with increasing elevation was possibly due to the effect of tree size. The acorn production of Odaesan for 3 years was 2.2 times greater than that of Seoraksan. This was presumed that there are more distribution of thick oak trees and more favorable site conditions such as deep soil A-layer depth, high organic matter, and slower slopes. Conclusion: As reported for other species of the genus Quercus, the acorn production of Q. mongolica showed large spatial and annual variations. The temporal variability was presumed to be a weather-influenced masting, while the spatial variability was mainly caused by oak tree size.

• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.19-33
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• 2022

Newmark's sliding block analysis is the most commonly used method for predicting earthquake-induced permanent displacement of embankment slopes. Additionally, it yields the amount of slip circle sliding using the limit equilibrium theory. Thus, permanent displacement does not occur until the seismic load exceeds the yield acceleration, which induces sliding of the slip circle. The evolution of Newmark's sliding block analysis has been made by introducing the numerical seismic response analysis results since it was introduced. This study compares seismic performance evaluation results for the example enclosure dam section with the analysis methods. As a result, earthquake-induced permanent displacement using Newmark's sliding block analysis did not occur for the enclosure dam, indicating a high safety factor. However, nonlinear response history analysis gave reasonable results.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.803-812
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• 2022

The purpose of this study is to examine whether non-self perspective(NSP) reduces the negative effects of life stress experienced by middle-aged adults. an online survey was conducted using a sample of 207 adult men and women in their 40s and 50s, and a hierarchical regression analysis and simple slope analysis were performed. As a result, it was found that NSP modulates the negative effects of life stress on perceived stress and subjective well-being. Specifically, NSP reduced the positive effect of life event stress on perceived stress and reduced the negative effect on subjective well-being. The results of this study suggest that eastern and Buddhist self-view, NSP, has a buffering effect on life stress experienced by middle-aged adults. This study suggests that NSP should be considered as an important factor for coping with stress in middle-aged adults in counseling and clinical settings, and is expected to promote subsequent empirical research on the Buddhist concept of non-self. Finally, limitations and future studies are suggested.

• Korean Journal of Agricultural Science
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• v.49 no.2
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• pp.317-330
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• 2022

Recently, the policy regarding climate change in Korea and overseas has been to promote the utilization of forest biomass to achieve net zero emissions. In addition, with the implementation of the unused forest biomass system in 2018, the size of the Korean market for manufacturing wood pellets and wood chips using unused forest biomass is rapidly expanding. Therefore, it is necessary to estimate the total amount of unused forest biomass that can be used as an energy source and to identify the capacity that can be continuously produced annually. In this study, we estimated the actual forest area that can be produced of logging residue and the potential amount of unused forest biomass resources based on GT (green ton). Using a forest functions classification map (1 : 25,000), 5th digital forest type map (1 : 25,000), and digital elevation model (DEM), the forest area with a slope of 30° or less and mountain ridges of 70% or less was estimated based on production forest and IV age class or more. The total forest area where unused forest biomass can be produced was estimated to be 1,453,047 ha. Based on GT, the total amount of unused forest biomass potential resources in Korea was estimated to be 117,741,436 tons. By forest type, coniferous forests were estimated to be 48,513,580 tons (41.2%), broad-leaved forests 27,419,391 tons (23.3%), and mixed forests 41,808,465 tons (35.5%). Data from this research analysis can be used as basic data to estimate commercial use of unused forest biomass.

• Fashion & Textile Research Journal
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• v.25 no.1
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• pp.92-103
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• 2023

As the body shape change which occurs after middle age is the main factor affecting the fit of ready-to-wear clothes, this study was designed to classify and analyze the torso shapes of middle-aged men. This study sorted 3D body scans of 200 men aged 40-64 from the 8th Size Korea (2021) database and extracted their 47 measurement values using the Grasshopper algorithm for automatic extraction landmarks and measurements, developed by the previous research (Ryu & Song, 2022). Eight principal components (torso length, shoulder size, overall body size, abdomen prominence, back protrusion, neck inclination, upper body slope, and hip prominence) were identified and four torso shapes were classified. Shape 1 (28.5%) exhibited the shortest torso length, the narrowest shoulders, and the most protruding back. Shape 2 (21.0%) exhibited the skinniest body and the largest backward inclination of the upper body. Hence, the back appeared to be protruding, and the abdomen looked prominent. Shape 3 (25.5%) had the largest overall body size. Thus, the abdomen looked the least protruding, and it exhibited the flattest back. Shape 4 (25.0%) had the longest torso, widest shoulders, straightest neck, and the least protruding hips. This study suggested these three discriminant functions to identify a new person's torso type.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.241-251
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• 2006

This study analyzed the topographical characteristics by extracting property factors of stream (stream order, number of stream, stream length, mean stream length) and property factors of basin (basin area, basin length, total stream length, total number of stream, basin mean width, form factor, maximum stream order, basin density, stream frequency, relief ratio, mean elevation, mean, slope, maximum elevation) from DEM (digital elevation model) and stream network generated by 1:5,000 NGIS (national geographical information system) data for the Bukhan-river basin. In addition, topographical factors for upper, mid stream and lower stream were analyzed and the mutuality of the factors by linear and nonlinear regression curve was identified.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.19-24
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• 2023

Ground anchor has been widely used specially for maintaining stability on reinforced cut slope in expressway. While the durability of the ground anchors should be ensured over the service life. However, the long-term loss of tensile force has occurred in most of field-installed anchors. Main causes are not clearly identified and very few studies have been made for analyzing long-term behavior of ground anchor in slopes. In this study, full-scale model tests and long-term measurements were made to obtain the load-displacement data and identified the causes of the long-term behaviors of ground anchor. As a result, the bond strength decreases exponentially with increasing water-binder ratio. Especially, groundwater is the most influencing factor to the bond strength. In the long-term behavior, the load decreases sharply until the initial settlement stabilized, and thereafter the tension force decreases constantly.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.58-58
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• 2022

본 연구는 국내 6곳의 풍혈의 기능과 식물분포를 통하여 풍혈의 보전대책과 관리방안을 위한 기초자료를 확보하기 위해 진행하였다. 조사는 홍천 방내리, 정선 여탄리, 정선 운치리, 연천 동막리, 제천 금수산, 보은 구병산에 위치하는 풍혈 6곳을 선정하였고 풍혈에 기상측정장비를 설치하여 2021년 3월부터 2022년 3월까지 온도와 습도의 미기상요인을 측정하였다. 풍혈이 위치하는 지역의 미기상요인은 기상청 자료를 활용하였고 측정된 풍혈의 미기상요인과 비교 분석하였으며, 관속식물상은 계절별로 진행하여 각 풍혈에 서식하는 희귀식물과 북방계식물, 기후변화 취약식물을 분석하였다. 풍혈 6곳의 미기상요인 분석결과 온도는 보은 구병산 풍혈을 제외한 5곳의 풍혈은 여름철 냉혈의 기능을 나타냈고, 보은 구병산 풍혈은 겨울철 온혈의 기능을 하는 것으로 나타났으며, 습도는 6곳 모두 주변 지역보다 높게 나타났다. 멸종위기종 2급은 백부자, 산작약, 연잎꿩의다리 3분류군, 희귀식물은 산개나리, 월귤 등 23분류군, 북방계식물은 과남풀, 꽃개회나무 등 129분류군, 기후변화취약식물은 검종덩굴, 도깨비부채 등 23분류군으로 확인되었다. 풍혈은 기후변화 취약식물의 피난처로서 역할을 하는 것으로 나타났으나 산림유전자원보호구역으로 지정된 홍천 방내리 풍혈을 제외한 나머지 풍혈은 관리가 미흡하다. 정선 여탄리 풍혈은 인근 도로에서의 외래식물의 유입, 정선 운치리 풍혈은 인근의 양봉장과 관광객 등의 인간활동에 의한 훼손, 연천 동막리 풍혈은 인근 경작지 등의 사유지로 인한 관리의 어려움, 제천 금수산 풍혈은 관광지화로 인한 훼손, 보은 구병산 풍혈은 등산객의 답압으로 인한 훼손이 진행되고 있는 것으로 나타났다. 이에 따라 풍혈과 희귀 및 기후변화 취약식물들의 정기적인 모니터링과 풍혈 주변의 팬스 설치 등의 적극적인 보전방안이 필요하다고 판단된다.