• Journal of Energy Engineering
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• v.27 no.4
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• pp.27-35
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• 2018

The passive containment cooling system (PCCS) has been designed to remove the released decay heat during the accident by means of the condensation heat transfer phenomenon to guarantee the safety of the nuclear power plant. The heat removal performance of the PCCS is mainly governed by the condensation heat transfer of the steam-air mixture. In this study, the heat removal performance of the PCCS was evaluated by using the MARS-KS code with a new empirical correlation for steam condensation in the presence of a noncondensable gas. A new empirical correlation implemented into the MARS-KS code was developed as a function of parameters that affect the condensation heat transfer coefficient, such as the pressure, the wall subcooling, the noncondensable gas mass fraction and the aspect ratio of the condenser tube. The empirical correlation was applied to the MARS-KS code to replace the default Colburn-Hougen model. The various thermal-hydraulic parameters during the operation of the PCCS follonwing a large-break loss-of-coolant-accident were analyzed. The transient pressure behavior inside the containment from the MARS-KS with the empirical correlation was compared with calculated with the Colburn-Hougen model.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.187-195
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• 2019

The needs for precise diagnostics and farm management-decision aids have increased to reduce the risk of climate change and environmental stress. Crop simulation models have been widely used to search optimal solutions for effective cultural practices. However, limited knowledge on physiological responses to environmental variation would make it challenging to apply crop simulation models to a wide range of studies. Advanced research facilities would help investigation of plant response to the environment. In the present study, the sunlit controlled environment chambers, known as Korean SPAR (Soil-Plant-Atmosphere-Research) system, was developed by renovating existing SPAR system. The Korean SPAR system controls and monitors major environmental variables including atmospheric carbon dioxide concentration, temperature and soil moisture. Furthermore, plants are allowed to grow under natural sunlight. Key physiological and physical data such as canopy photosynthesis and respiration, canopy water and nutrient use over the whole growth period are also collected automatically. As a case study, it was shown that the Korean SPAR system would be useful for collection of data needed for understanding the growth and developmental processes of a crop, e.g., soybean. In addition, we have demonstrated that the canopy photosynthetic data of the Korean SPAR indicate the precise representation of physiological responses to environment variation. As a result, physical and physiological data obtained from the Korean SPAR are expected to be useful for development of an advanced crop simulation model minimizing errors and confounding factors that usually occur in field experiments.

• Health Policy and Management
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• v.29 no.1
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• pp.58-67
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• 2019

Background: In this study, we aimed to investigate the drinking behaviors and drinking-related problems of college students in South Korea to produce national alcohol statistics. Methods: We carefully examined the questionnaires and previous research developed in the previous research project and selected questions that reflect the special environment and culture of college students. In order to stratify a nationally representative sample of college students, the distribution of students around the country were found through the educational statistics database of the Korea Educational Development Institute. Based on this information, we conducted a survey in collaboration with Gallup (Korea) to survey and analyze the drinking behaviors of 5,024 Korean students. Results: A nationwide cross-sectional survey was conducted in 2017, for Korean college students. A total of 5,024 students were recruited and analyzed. The monthly drinking rate was 78.0% for male students and 72.9% for female students. The high-risk drinking rate was 23.3% for male students and 17.2% for female students. The most popular category for number of drinks per drinking session was 'more than 10 glasses' per drinking session for both male (44.1%) and female (32.8%). On the alcohol use disorders identification test, the greatest proportion of male students were in the high-risk drinking category (score 8 to 15) 43.8%, followed by the 'low-risk drinking' (score 0 to 7) in 43.6%, 'alcohol abuse' (score 16 to 19) 7.2%, and 'alcohol dependence' (greater than 20) 5.4% categories, respectively. For female students, the greatest proportion of female students were in the 'low-risk drinking' in 49.6%, followed by 'high-risk drinking' 37.1%, 'alcohol abuse' 8.4%, and 'alcohol dependence' 4.9% categories, respectively. Conclusion: The results of the study showed that the drinking behavior of Korean college students was excessive. Overall, it was found that the college population has a greater high-risk drinking behaviors than general adult population. Furthermore, these problem drinking behaviors were prominent among female college students. Results from the present study suggest that it is necessary to monitor the drinking behavior of college students with constant interest and to prepare policies and strategies suitable for these circumstances.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.285-291
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• 2018

The System of Rice Intensification (SRI) has been spread very quickly in southern Cambodia. To understand the motivation of farmers in adapting SRI, and its benefits, we conducted an on-farm study at Popel commune, Tramkak district, Takeo province in southern Cambodia, during the 2012 and 2013 wet season. We noticed a significant difference between SRI and conventional farmers' practices (FP) in rainfed lowland rice ecosystem. Despite of low nitrogen input, without chemical fertilizers, high grain yield was achieved in SRI 1 (6.0 t ha) and SRI2-Bottom ($7.2t\;ha^{-1}$) in 2013. SRI 1 and SRI 2 of panicle and number of panicle were high than SR 3, FP 2, and FP 3 due to early transplant. Relationships between total number of spikelet and plant nitrogen were ($r^2=0.95$) highly positive at harvest. SRI fields were, most of them achieving highly superior yield and number of panicle compared to their FP fields. The results indicated that SRI practices of planting younger seedling, with organic material and topography of paddy, lead to increased grain yield.

• Journal of the Korean Wood Science and Technology
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• v.49 no.2
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• pp.107-121
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• 2021

The purpose of this study is to optimize the bonding method of the plywood suitable for cross-laminated timber (CLT) with plywood as a core by analyzing the flexural performance and failure mode according to the lamina species, the method of bonding plywood in the longitudinal direction, and whether or not adhesive is applied to the joint. In the case of the Douglas fir lamina layer, the modulus of elasticity decreased by about 11.5% due to longitudinal bonding, and the modulus of rupture increased or decreased according to the adhesive application and bonding method. The optimal conditions were derived as the butt joint without adhesive, half lap joint with adhesive, and butt joint. In the case of the larch lamina layer, the modulus of rupture and the modulus of elasticity decreased by about 15% and 40%, respectively. When using the half lab joint and tongue & groove joint, it is believed that it reduces the load transmitted to the middle layer by primarily preventing the failure on flexure at the joint of the plywood layer. From the results of this study, the larch lamina layer used in the manufacturing process of Ply-lam CLT did not show any difference based on the bonding method. Butt joint and half lap joint bonding method are determined to be suitable when using Douglas fir lamina layer.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.83-88
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• 2021

Life cycle stages, including daughter sporocysts, cercariae, and metacercariae, of Parvatrema duboisi (Dollfus, 1923) Bartoli, 1974 (Digenea: Gymnophallidae) have been found in the Manila clam Ruditapes philippinarum from Aphae-do (Island), Shinan-gun, Jeollanam-do, Korea. The daughter sporocysts were elongated sac-like and 307-570 (av. 395) ㎛ long and 101-213 (av. 157) ㎛ wide. Most of the daughter sporocysts contained 15-20 furcocercous cercariae each. The cercariae measured 112-146 (av. 134) ㎛ in total length and 35-46 (av. 40) ㎛ in width, with 69-92 (av. 85) ㎛ long body and 39-54 (av. 49) ㎛ long tail. The metacercariae were 210-250 (av. 231) ㎛ in length and 170-195 (av. 185) ㎛ in width, and characterized by having a large oral sucker, genital pore some distance anterior to the ventral sucker, no ventral pit, and 1 compact or slightly lobed vitellarium, strongly suggesting P. duboisi. The metacercariae were experimentally infected to ICR mice, and adults were recovered at day 7 post-infection. The adult flukes were morphologically similar to the metacercariae except in the presence of up to 20 eggs in the uterus. The daughter sporocysts and metacercariae were molecularly (ITS1-5.8S rDNA-ITS2) analyzed to confirm the species, and the results showed 99.8-99.9% identity with P. duboisi reported from Kyushu, Japan and Gochang, Korea. These results confirmed the presence of various life cycle stages of P. duboisi in the Manila clam, R. philippinarum, playing the role of the first as well as the second intermediate host, on Aphae-do (Island), Shinan-gun, Korea.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.289-316
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• 2022

This study was investigated to elucidate the distribution of vascular plants and their usefulness of Seondalsan Mountain (1,236 m) in Bonghwa-gun, Gyeongsangbuk-do. The surveys were carried out 20 times from April in 2014 to October in 2020. The vascular plants of Seondalsan Mountain was consisted a total of 638 taxa based on the voucher specimens; 96 families, 341 genera, 562 species, 18 subspecies, 53 varieties, 5 forms. 20 taxa of the Korean endemic plants were recorded and 1 taxa of Critically Endangered (CR), 3 taxa of Vulnerable (VU) and 9 taxa of Least Concern (LC), designated by Korean Forest Service as rare plants, were investigated in this region. Furthermore, V, IV and III degrees of floristic regional indicator plants, designated by the National Institute of Ecology, were included 1 taxa, 11 taxa and 28 taxa, respectively. Among them, edible, medicinal, fragrant, industrial, ornamental, ecological restoration, forage/compost plants were included 440 taxa, 505 taxa, 19 taxa, 234 taxa, 335 taxa, 214 taxa and 269 taxa respectively. In addition, 30 taxa of naturalized plants were observed.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.3
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• pp.67-73
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• 2022

This study tracked the changing process of unregistered private house gardens by using the form at the time of the construction of gardens as the prototype of each garden, investigated the spatial value of the garden, and discussed the historical spatial value of unregistered private house gardens in terms of inheritance and change of traditional gardens. To this end, targeting on unregistered private house gardens in Gangwon-do, which are in danger of preserving their gardens due to the recent increase in the number of designated cultural heritage dismantled, the patterns of unregistered private house gardens, their characteristics and values were identified through the spatial change of the garden, and the following results were derived. First, the unregistered private house gardens were able to inherit and maintain the form of a traditional garden, being located in a clan village. The garden space was divided by the influence of Confucian philosophy, and the components of the garden, tree species and planting methods appeared differently. In other words, the use of garden components according to the status hierarchy appeared. Second, space reduction was continuously confirmed at four target sites. The reduced spaces are garden spaces, and part of the garden was attributed to the state due to the building of new road and environmental improvement project. The reduced spaces are garden spaces, and part of the garden was attributed to the state due to the new road and environmental improvement project. Third, eight old big trees over 100 years old were identified in three of the four target sites, and the garden components such as stone water tanks, quickset doors, and ponds were commonly identified in Korea, China, and Japan during the Joseon Dynasty, inheriting the historicity of the traditional garden.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.454-462
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• 2023

Flash lamp annealing (FLA) of metal nanoparticle (NP) ink has provided powerful strategies to fabricate high-performance electrodes on a flexible substrate because of its rapid processing capability (in milliseconds), low-temperature process, and compatibility with to roll-to-roll process. However, metal NPs [e.g., gold (Au), silver (Ag), copper (Cu), etc.] have limitations such as difficulty in synthesizing fine metal NPs (diameter less than 10 nm), high price, and degradation during ink storage and FLA processing. In this regard, organometallic ink has been proposed as a material that can replace metal NPs due to their low-cost (usually 1/100 times cheaper than metal nano inks), low-temperature processability, and high material stability. Despite these advantages, the fabrication of flexible electrodes through FLA treatment of organometallic compounds has not been extensively researched. In this paper, we experimentally guide how to determine the optimal conditions for forming electrodes on flexible substrates by considering material parameters, and flashlight processing parameters (energy density, pulse duration, etc) to minimize the difficulties that may arise during the FLA of organometallic ink.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.365-373
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• 2023

Since the lips are a representative facial part that can express human attraction, aesthetic interest in them has always existed in human history. However, as lips age, they tend to form wrinkles, become thinner, and lose their volume. To counteract this phenomenon, medical procedures such as fillers or fat transplantation have been suggested. In this study, we verified that the one of main effective material complex of L G H&H L IPCERIN^®, combination of cedrol, a sesquiterpene found in cedarwood, and three peptides (acetyl hexapeptide-8, acetyl tetrapeptide-9, and desamidocollagen) could ameliorate the photo-aging and reduce the wrinkles through in vitro experiments. The possibility of improving collagen and elastin expression in skin fibroblasts and reducing MMP expression under photoaging conditions was verified. In addition, it was confirmed that the amount of fat tissue in the lips can be increased by promoting adipose stem cell differentiation and increasing the amount of fat produced in the in vitro adipose stem cell differentiation experiment. Two weeks of human application tests confirmed that a combination of cedrol and peptides can improve the wrinkles, texture, elasticity, and volume of the lips. This study verified that the combination of cedrol and three peptides can be used as effective cosmetic materials to decrease the various signs of aging in the lips.