• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.40-49
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• 2019

Coarse woody debris (CWD), which is a component of the forest ecosystem, plays a major role in forest energy flow and nutrient cycling. In particular, CWD isolates carbon for a long time and is important in terms of slowing the rate of carbon released from the forest to the atmosphere. Therefore, this study measured the physiochemical characteristics and respiration rate ($R_{CWD}$) of CWD for Larix kaempferi and Pinus rigida in temperate forests in central Korea. In summer 2018, CWD samples from decay class (DC) I to IV were collected in the 14 forest stands. $R_{CWD}$ and physiochemical characteristics were measured using a closed chamber with a portable carbon dioxide sensor in the laboratory. In both species, as CWD decomposition progressed, the density ($D_{CWD}$) of the CWD decreased while the water content ($WC_{CWD}$) increased. Furthermore, the carbon concentrations did not significantly differ by DC, whereas the nitrogen concentration significantly increased and the C/N ratio decreased. The respiration rate of L. kaempferi CWD increased significantly up to DC IV, but for P. rigida it increased to DC II and then unchanged for DC II-IV. Accordingly, except for carbon concentration, all the measured characteristics showed a significant correlation with $R_{CWD}$. Multiple linear regression showed that $WC_{CWD}$ was the most influential factor on $R_{CWD}$. $WC_{CWD}$ affects $R_{CWD}$ by increasing microbial activity and is closely related to complex environmental factors such as temperature and light conditions. Therefore, it is necessary to study their correlation and estimate the time-series pattern of CWD moisture.

• Journal of Nutrition and Health
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• v.55 no.1
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• pp.120-140
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• 2022

Purpose: The purpose of the study was to investigate whether adherence to the Korea Healthy Eating Index (KHEI) was associated with metabolic syndrome and risk markers. Methods: The participants included 8,345 adults, aged 20-59 years, who took part in the 7th Korea National Health and Nutrition Examination Survey (KNHANES). The data were analyzed using a complex-sample t-test, the Rao Scott χ²-test, and logistic regression analysis on the SPSS v. 26.0 software. The participants were divided into four groups by quartiles of KHEI scores. Results: The average KHEI score was 61.06 points out of 100, and the women's score (62.50 points) was significantly higher than that of men (59.63 points). The KHEI quartiles status showed significant differences by age (p < 0.001), household income (p < 0.001), smoking status (p < 0.001), and food security. Specifically, the KHEI quartiles in the men showed significant differences in education (p < 0.001) and economic activity (p < 0.001) whereas those of women showed significant differences in alcohol-consumption (p < 0.001), depression (p < 0.01) and eating-out (p < 0.001). As the KHEI scores increased, the proportion of subjects with an energy intake below the estimated energy requirement (EER) was lower, and significantly better levels of intake were observed for carbohydrate, protein, vitamin C, calcium, vitamin B₁, vitamin B₂, and niacin. The incidence of the metabolic syndrome risk factors, hypertriglyceridemia and hyperglycemia for men and hypertension, and hyperglycemia for women showed significant differences. The KHEI scores were inversely associated with abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol, hyperglycemia, hypertension, and metabolic syndrome. Conclusion: Based on these results, we conclude that higher adherence to the KHEI was associated with lower metabolic syndrome risk factors and incidence of the metabolic syndrome.

• Journal of Nutrition and Health
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• v.56 no.4
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• pp.439-453
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• 2023

Purpose: Concerns about accelerated aging are regularly being discussed. This study analyzed the dietary status and nutritional intake of college students who are about to enter their 30s and 40s. We further suggest ways to eat healthily. Methods: Totally, 67 students attending Daegu Catholic University were provided with a three-day meal record and analyzed. Results: The average demographics of the subjects were as follows: age 23.2 ± 2.0 years, height 165.1 ± 9.0 cm, weight 65.4 ± 13.6 kg, and BMI 23.5 ± 3.9 kg/m². Overall, 76.3% of the subjects skipped breakfast. The food intake evaluation according to the food group intake pattern and the recommended number of servings determined that 38.3% of the subjects did not consume fruits and dairy products (GMVFDS = 111001), and both men and women lacked all food groups. Analysis of the nutrient intake state revealed lesser nutrient intake than the estimated energy need. Evaluation of the %RDA found that consumption of phosphorus was above the recommended amount, whereas all other nutrients were below the recommended amount. Men had a higher intake rate of phosphorus (p < 0.01), iron (p < 0.001), and sodium (p < 0.05) than women, whereas the intake rate of dietary fiber was higher in women (p < 0.05). Evaluation of the food intake by 22 food categories revealed that intake of regular grains was more in men than in women (p < 0.05) whereas women consumed significantly more mixed grains (p< 0.01). In protein foods, men consumed more meat (p < 0.01), while women consumed more eggs (p < 0.05) and beans (p < 0.05). Evaluating the fruit intake, juices were more frequently consumed by men than by women (p < 0.05). No differences were obtained in food intake and nutrient intake status according to obesity. Conclusion: Based on these results, there is an urgent requirement for attention and support for university cafeterias in order to induce changes in the eating habits of college students. Among other initiatives, this can be achieved by providing diet improvement programs and menus that consider food preferences.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.435-445
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• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• Conservation Science in Museum
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• v.31
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• pp.21-37
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• 2024

This paper sought to garner an understanding of Daegaya glass culture by observing the micro-structure and analyzing the chemical composition of 43 glass beads excavated from the No.73 and 74 ancient tombs in Jisan-dong, Goryeong, which are estimated to have a central age of 5th century CE. The visible characteristics and micro-structure of these artifacts were observed with a optical microscope and an scanning electron microscope, while their chemical composition was analyzed with an energy-dispersing spectrometer attached to the scanning electron microscope. As a result, the glass beads of Jisan-dong, Goryeong were identified to have been formed using various methods such as drawing, casting, and folding techniques, with the majority molded by the drawing technique. In terms of chemical composition, 32.6% were in the potash glass group and 67.4% in the soda glass group, with the latter divided into various fluxes such as high alumina glass, netron glass, and plant ash glass. Compared to Baekje's cultural region in the same age, the composition of these ancient glass artifacts demonstrates a high share of the potash glass group. This shows that, despite the shift from the potash glass group to the soda glass group in ancient Korean glass culture, glass composition differs from region to region or depending on the cultural sphere of influence. In the soda glass group, high-alumina glass comprised 23.3%, natron glass 43.0%, and plant ash glass was 1.2%. Among them, the main type of Korean soda glass is high-alumina glass, as natron glass and plant ash glass are known to have appeared later, but the results of scientific analysis of the glass beads excavated in Jisan-dong can be expected to provide important clues about the inflow and transformation of ancient glass on the Korean Peninsula. In the No. 73, 74, and 74-1 ancient tombs, which were found to have been built in chronological order by the excavation survey, the glass beads showed only slight variations depending on their production period. Nonetheless, the chemical composition of glass is deemed to have a close correlation to color.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.349-356
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• 2006

We have investigated adsorption and desorption properties of CO adsorption on silica supported Ru/Ni alloys at various Ru/Ni mole content ratio as well as CO partial pressures using Fourier transform infrared spectrometer (FT-IR). For Ru-$SiO_{2}$ sample, four bands were observed at $2080.0cm^{-1}$, $2021.0{\sim}2030.7cm^{-1}$, $1778.9{\sim}1799.3cm^{-1}$, $1623.8cm^{-1}$ on adsorption and three bands were observed at $2138.7cm^{-1}$, $2069.3cm^{-1}$, $1988.3{\sim}2030.7cm^{-1}$ on vacumn desorption. For Ni-$SiO_{2}$ sample, four bands were observed at $2057.7cm^{-1}$, $2019.1{\sim}2040.3cm^{-1}$, $1862.9{\sim}1868.7cm^{-1}$, $1625.7cm^{-1}$ on adsorption and two bands were observed at $2009.5{\sim}2040.3cm^{-1}$, $1828.4{\sim}1868.7cm^{-1}$ on vacumn desorption. These absorption bands correspond with those of the previous reports approximately. For Ru/Ni(9/1, 8/2, 7/3, 6/4, 5/5; mole content ratio)-$SiO_{2}$ samples, three bands were observed at $2001.8{\sim}2057.7cm^{-1}$, $1812.8{\sim}1926.5cm^{-1}$, $1623.8{\sim}1625.7cm^{-1}$ on adsorption and three bands were observed at $2140.6cm^{-1}$, $2073.1cm^{-1}$, $1969.0{\sim}2057.7cm^{-1}$ on vacumn desorption. The spectrum pattern observed for Ru/Ni-$SiO_{2}$ sample at 9/1 Ru/Ni mole content ratio on CO adsorption and on vacumn desorption is almost like the spectrum pattern observed for Ru-$SiO_{2}$ sample. But the spectrum patterns observed for Ru/Ni-$SiO_{2}$ samples under 8/2 Ru/Ni mole content ratio on CO adsorption and vacumn desorption are almost like the pattern observed for $Ni-SiO_{2}$ sample. It may be suggested surfaces of alloy clusters on the Ru/Ni-$SiO_{2}$ samples contain more Ni components than the mole content ratio of the sample considering the above phenomena. With Ru/Ni-$SiO_{2}$ samples the absorption band shifts may be ascribed to variations of surface concentration, strain variation due to atomic size difference, variation of bonding energy and electronic densities, and changes of surface geometries according to surface concentration variation. Studies for CO adsorption on Ru/Ni alloy cluster surface by LEED and Auger spectroscopy, interation between Ru/Ni alloy cluster and $SiO_{2}$, and MO calculation for the system would be needed to look into the phenomena.