• Clean Technology
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• v.30 no.2
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• pp.134-144
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• 2024

In this study, the mechanical stability of red mud was improved for its commercial use as a catalyst to effectively decompose HFC-134a, one of the seven major greenhouse gases. Red mud is an industrial waste discharged from aluminum production, but it can be used for the decomposition of HFC-134a. Red mud can be manufactured into a catalyst via the crushing-preparative-compression molding-firing process, and it is possible to improve the catalyst performance and secure mechanical stability through calcination. In order to determine the optimal heat treatment conditions, pellet-shaped compressed red mud samples were calcined at 300, 600, 800 ℃ using a muffle furnace for 5 hours. The mechanical stability was confirmed by the weight loss rate before and after ultra-sonication after the catalyst was immersed in distilled water. The catalyst calcined at 800 ℃ (RM 800) was found to have the best mechanical stability as well as the most catalytic activity. The catalyst performance and durability tests that were performed for 100 hours using the RM 800 catalyst showed thatmore than 99% of 1 mol% HFC-134a was degraded at 650 ℃, and no degradation in catalytic activity was observed. XRD analysis showed tri-calcium aluminate and gehlenite crystalline phases, which enhance mechanical strength and catalytic activity due to the interaction of Ca, Si, and Al after heat treatment at 800 ℃. SEM/EDS analysis of the durability tested catalysts showed no losses in active substances or shape changes due to HFC-134a abasement. Through this research, it is expected that red mud can be commercialized as a catalyst for waste refrigerant treatment due to its high economic feasibility, high decomposition efficiency and mechanical stability.

• Korean Journal of Plant Resources
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• v.37 no.2
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• pp.120-129
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• 2024

Alcoholic liver disease (ALD) is a significant risk factor in the global disease burden. The stem bark of the Betulaceae plant Alnus japonica, which is indigenous to Korea, has been used as a popular folk medicine for hepatitis and cancer. However, the preventive effect of Alnus japonica leaf extracts on alcohol-related liver damage has not been investigated. The objective of this study was to investigate the hepatoprotective effects of the extracts of Alnus japonica leaf (AJL) against ethanol-induced liver damage in HepG2/2E1 cells. Treatment with AJL significantly prevented ethanol-induced cytotoxicity in HepG2/2E1 cells by reducing the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). This protective effect was likely associated with antioxidant potential of AJL, as evidenced by the attenuation of reactive oxygen species (ROS) and malondialdehyde (MDA) production and restoration of the depleted glutathione (GSH) levels in ethanol-induced HepG2/2E1 cells. Our findings suggest that FCC might be considered as a useful agent in the prevention of liver damage induced by oxidative stress by increasing the antioxidant defense mechanism.

• Education of Primary School Mathematics
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• v.27 no.2
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• pp.111-137
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• 2024

The purpose of this study is to identify the expected difficulties and necessary support when applying the 2022 revised mathematics curriculum to elementary schools, and to support the establishment of the field. To this end, we explored the major changes in the 2022 revised mathematics curriculum, and based on this, we conducted a survey of elementary school teachers to identify the expected difficulties and necessary support when applying it in the field. In particular, when analyzing the results, we also examined whether there were any differences in the expected difficulties and necessary support depending on the size of the school where it is located and the teaching experience of the teacher. The research results are as follows. First, the proportion of teachers who expect difficulties in applying the 2022 revised mathematics curriculum was mostly below 50%, but the proportion of teachers who demand support was much higher, at around 80%. Second, the difficulty of elementary school teachers in applying the 2022 revised mathematics curriculum was found to be the greatest in evaluation. Third, in relation to the use of edutech, teachers in elementary schools are also expected to have difficulties in teaching and learning methods to foster students' digital literacy, assessment using teaching materials or engineering tools, and assessment in online environments. Fourth, the difficulty of elementary school teachers in applying the 2022 revised mathematics curriculum was also significant in relation to mathematics subject competencies. Fifth, it was found that there is also difficulty in understanding the major changes of the achievement standards, including the addition, deletion, and adjustment of the achievement standards, and the impact on the learning of other achievement standards. Finally, the responses of elementary school teachers to the expected difficulties and necessary support in applying the 2022 revised mathematics curriculum did not differ depending on the size of the school where it is located, but statistically significant differences were found in a number of items depending on the teaching experience of the teacher. Based on these research results, we hope that various support will be provided for the 2022 revised mathematics curriculum, which will be applied annually from 2024.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.161-175
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• 2024

Aggregate typically refers to sand and gravel formed by the transportation of rocks in rivers or artificially crushed, constituting a core resource in the construction industry. Gyeongsangbuk-do, the largest administrative area in South Korea, produces various sources of gravel, including forest, land (excluding other sources), river, and crushed stone. As of 2022, it has extracted approximately 6.96 million cubic meters of aggregate, with permitted production totaling around 4.07 million cubic meters and reported production of about 2.88 million cubic meters. The aggregate demand in Gyeongsangbuk-do is estimated to be 12.39 million cubic meters according to the estimation method in Ready-Mix Concrete. From the supply perspective, about 120 extraction sites are operational, with most municipalities maintaining an appropriate balance between aggregate demand and supply. However, in some areas, there is inbound and outbound transportation of aggregate to neighboring regions. Regions with significant inbound and outbound aggregate transportation in Gyeongsangbuk-do are areas connected to Daegu Metropolitan City and Pohang City along the Gyeongbu rail line, showing a high correlation with population distribution. Gyeongsangbuk-do faces challenges such as population decline, aging rural areas, and insufficient balanced regional development. Analysis using GIS reveals these trends in gravel demand and supply. Currently in this study, Gyeongsangbuk-do meets its demand for aggregate through the supply of various aggregate sources, maintaining stable aggregate procurement. River and terrestrial aggregates may be sustained as short-term supply strategies due to the difficulty of longterm development. Considering the reliance on raw material supply for selective crushing, it suggests the need for raw material management to maintain stability. Gyeongsangbuk-do highlights quarries in the forest as an important resource for sustainable aggregate supply, advocating for the development of large-scale aggregate quarries as a long-term alternative. These research findings are expected to provide valuable insights for formulating strategies for sustainable management and stable utilization of aggregate resources.

• Journal of Life Science
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• v.34 no.4
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• pp.254-263
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• 2024

Korean jang is a food made using fermented soybeans, and the typical products include gochujang (GO), doenjang (DO), cheonggukjang (CH), and ganjang (GA). In this study, 16S rRNA metagenome analysis was performed on a total of 200 types of GO, DO, CH, and GA using next-generation sequencing to analyze the microbial community of fermented soybean foods and compare taxonomic (biomarker) differences. Alpha diversity analysis showed that in the CHAO index, the species richness index tended to be significantly higher compared to the DO and GA groups (p<0.001). The results of the microbial distribution analysis of the GO, DO, CH, and GA products showed that at the order level, Bacillales was the most abundant in the GO, DO, and CH groups, but Lactobacillales was most abundant in the GA group. Linear discriminant analysis effect (LEfSe) analysis was used to identify biomarkers at the family and species levels. Leuconostocaceae, Thermoactinomycetaceae, Bacillaceae, and Enterococcaceae appeared as biomarkers at the family level, and Bacillus subtilis, Kroppenstedtia sanguinis, Bacillus licheniformis, and Tetragenococcus halophilus appeared at the species level. Permutational multivariate analysis of variance (PERMANOVA) analysis showed that there was a significant difference in the microbial community structure of the GO, DO, CH, and GA groups (p=0.001), and the microbial community structure of the GA group showed the greatest difference. This study clarified the correlation between the characteristics of Korean fermented foods and microbial community distribution, enhancing knowledge of microorganisms participating in the fermentation process. These results could be leveraged to improve the quality of fermented soybean foods.

• Korean Journal of Environment and Ecology
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• v.37 no.6
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• pp.429-438
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• 2023

The forest in the lower Tumen River serves as an important ecosystem spanning the territories of North Korea, Russia, and China, and it provides habitat and movement corridors for diverse mammals, including the endangered Amur tiger (Panthera tigris) and Amur leopard (Panthera pardus). This study focuses on the Mijiang area, situated as a potential ecological corridor connecting North Korea and China in the lower Tumen River, playing a crucial role in conserving and restoring the biodiversity of the Korean Peninsula. This study aimed to identify mammal species and estimate their relative abundance, occupancy, and distribution based on the 48 camera traps installed in the Mijiang area from May 2019 to May 2021. The results confirmed the presence of 18 mammal species in the Mijiang area, including large carnivores like tigers and leopards. Among the dominant mammals, four species of ungulates showed high occupancy and detection rates, particularly the Roe deer (Capreolus pygargus) and Wild boar (Sus scrofa). The roe deer was distributed across all areas with a predicted high occupancy rate of 0.97, influenced by altitude, urban residential areas, and patch density. Wild boars showed a predicted occupancy rate of 0.73 and were distributed throughout the entire area, with factors such as wetland ratio, grazing intensity, and spatial heterogeneity in aspects of the landscape influencing their occupancy and detection rates. Sika deer (Cervus nippon) exhibited a predicted occupancy rate of 0.48, confined to specific areas, influenced by slope, habitat fragmentation diversity affecting detection rates, and the ratio of open forests impacting occupancy. Water deer (Hydropotes inermis) displayed a very low occupancy rate of 0.06 along the Tumen River Basin, with higher occupancy in lower altitude areas and increased detection in locations with high spatial heterogeneity in aspects. This study confirmed that the Mijiang area serves as a habitat supporting diverse mammals in the lower Tumen River while also playing a crucial role in facilitating animal movement and habitat connectivity. Additionally, the occupancy prediction model developed in this study is expected to contribute to predicting mammal distribution within the disrupted Tumen River basin due to human interference and identifying and protecting potential ecological corridors in this transboundary region.

• Korean Journal of Plant Resources
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• v.37 no.1
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• pp.87-92
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• 2024

'Miha' is a new strawberry (Fragaria x ananassa Duch.) cultivar, which was released by the Highland Agriculture Research Institute in 2019. The 'Miha' cultivar originates from a 2014 cross between 'Monterey' and 'Saebong No. 3', both of which exhibited excellent ever-bearing characteristics, including continuous flowering and large fruits under long-day and high temperature conditions. This new cultivar was initially named 'Saebong No. 12' after examining its characteristics and productivity during summer cultivation between 2015 and 2019. After regional adaptability tests, 'Miha' was selected from 'Saebong No. 12' as an elite cultivar. The general characteristics of 'Miha' include intermediate, elliptic leaves, and strong growth. The fruits are conical and of a dark-red color. The number of leaves of 'Miha' was 21.9, which was 6.2 fewer than that of the control cultivar, 'Goha' with 28.1. The number of flower clusters of 'Miha' was similar to that of 'Goha'. The average fruit weight of 'Miha' was 13.4 g, which was 4.3 g heavier than that of 'Goha'. The fruit hardness of 'Miha' was 36.2 g·mm^-2, which was 10.1 g·mm^-2 harder than that of 'Goha'. The marketable yield of 'Miha' was 37,393 kg·ha^-1, 156% more than that of 'Goha' with 23,970 kg·ha^-1. Therefore, the new cultivar of ever-bearing strawberry 'Miha' is expected to be very popular in the export or bakery market because it is hard.

• Journal of the Daesoon Academy of Sciences
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• v.47
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• pp.1-37
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• 2023

This essay seeks to answer the question of how best to understand Korean new religious movements (KNRMs). KNRMs have the characteristics of folk religion, ethno-religion, or popular religion. KNRMs are products of the national consciousness promoted by Korean society during the Late Joseon Dynasty at the turning point of modern Yi-Jing Studies. From the perspective of social evolutionary theory of developmental history, during that period, Joseon (Korea), like China, was faced with a double-edged sword consisting of the strength of tradition and the upheaval of modernity. If the strength of tradition depended on the Yi-Jing Studies to promote national enlightenment toward anti-imperialist aims, then it was equally the case that modernity depended on the sense of urgency to guide the people to secure livelihoods and edification regarding anti-feudalism. In this essay, the KNRMs that appeared during this transition period of Yi-Jing Studies will be a significant focus, and the worldview of Daesoon Thought will be the main focus. As one of the central topics, intensive discussion will be dedicated to the issue of the nature of pre-experientialism (先驗主義) which characterized the Great Opening (開闢). The principles of Daesoon Thought have a religious dimension of realistic awareness that guides the people's lives and edifies them. The process of the Great Opening aims to secure an ontological clock that tracks the Great Itineration of the world toward Daesoon Truth. This in turn as a process establishes the epistemological world of the Reordering Works of Heaven and Earth (天地公事) and reaches the axiological boundary of the future world. The links among the Three Realms is characterized by a pre-experientialist line that experiences the space-time nature of the universe as the Great Opening of the Later World (後天) within the framework of Heaven and Earth. Throughout this course, humans look to enjoy the infinite vitality of the universe from within their own finite vitality. Therefore, Daesoon Thought can overcome perceived reality through pre-experientialist channels such as the Great Opening of the Later World and aim for a state of self-awareness such as the Earthly Paradise. This is an attempt to participate and practice in the actual world rather than pursuing a world of transcendental ideas, and therefore, it tends to be proactive in the world rather than exhibit a passive tendency to be worldliness. In conclusion, the truth of Daesoon Thought, which is characterized by the Great Opening of the Later World, contains a future-oriented outlook that longs for a Nextopia full of hope and promise rather than idealistic fancy towards a Utopia or well-founded dread and disdain towards Dystopia.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.2
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• pp.77-100
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• 2024

Circulation, tides, currents, harmful algal blooms, water quality, and hypoxic conditions in Jinhae-Masan Bay have been extensively studied. However, these previous studies primarily focused on short-term variations, and there was limited detailed investigation into the physical mechanisms responsible for ocean circulation in the bays. Oceanic processes in the bays, such as pollutant dispersal, changes on a seasonal time scale. Therefore, this study aimed to understand how the circulation in Jinhae-Masan Bay varies seasonally and to examine the effects of tides, winds, and river discharges on regional ocean circulation. To achieve this, a three-dimensional ocean circulation model was used to simulate circulation patterns from 2016 to 2018, and sensitivity experiments were conducted. This study reveals that convective estuarine circulation develops in Jinhae and Masan Bays, characterized by the inflow of deep oceanic water from the Korea Strait through Gadeoksudo, while surface water flows outward. This deep water intrusion divides into northward and westward branches. In this study, the volume transport was calculated along the direction of bottom channels in each region. The meridional water exchange in the eastern region of Jinhae Bay is 2.3 times greater in winter and 1.4 times greater in summer compared to that of zonal exchange in the western region. In the western region of Jinhae Bay, the circulation pattern varies significantly by season due to changes in the balance of forces. During winter, surface currents flow southward and bottom currents flow northward, strengthening the north-south convective circulation due to the combined effects of northwesterly winds and the slope of the sea surface. In contrast, during summer, southwesterly winds cause surface seawater to flow eastward, and the elevated sea surface in the southeastern part enhances northward barotropic pressure gradient intensifying the eastward surface flow. The density gradient and southward baroclinic pressure gradient increase in the lower layer, causing a strong westward inflow of seawater from Gadeoksudo, enhancing the zonal convective circulation by 26% compared to winter. The convective circulation in the western Jinhae Bay is significantly influenced by both tidal current and wind during both winter and summer. In the eastern Jinhae Bay and Masan Bay, surface water flows outward to the open sea in all seasons, while bottom water flows inward, demonstrating a typical convective estuarine circulation. In winter, the contributions of wind and freshwater influx are significant, while in summer, the influence of mixing by tidal currents plays a major role in the north-south convective circulation. In the eastern Jinhae Bay, tidally driven residual circulation patterns, influenced by the local topography, are distinct. The study results are expected to enhance our understanding of pollutant dispersion, summer hypoxic events, and the abundance of red tide organisms in these bays.