• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.6
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• pp.639-646
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• 2022

Energy harvesting technologies that can convert wasted various energy into usable electrical energy have been widely investigated to overcome the limitation of batteries for the powering of IoT sensors and small electronic devices. Hybrid energy harvesting is known as a technology that enhances the output power of single energy harvesting device by housing two or more various energy harvesting mechanisms. In this study, we introduce a hybrid MME (Magneto-Mechano-Electric) generator coupled with the triboelectric effect. Through FEA modeling, four triboelectric materials, including PI (Polyimide), PFA(Teflon), Cu, and Al, were selected and compared with the expected triboelectric potentials. The effect of surface morphology was investigated as well. Among various combination of triboelectric materials and surface morphologies, PFA-Al combination with the surface morphology having nano-scale square projections showed highest output potential under triboelectrification. It is also experimentally confirmed that output voltage and power of the hybrid MME generator with triboelectric material combinations.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.51-59
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• 2023

The Nakdong river is both a natural resource crucial to underwater ecosystems and a water source for its basin's residents. Industrial wastewater and domestic sewage must meet the relevant standards for discharged water before they can flow into the river. The correlation between old and new measures of organic matter was examined using water quality data from 50 monitoring locations in the main stream of the Nakdong river. The coefficient of determination (R²) for total organic carbon (TOC), the new measure of organic matter, and chemical oxygen demand (COD), the old measure of organic matter, in the main stream of the Nakdong river was 0.6134, indicating high correlation. Water quality at each location assessed using TOC and COD showed disparities that cannot be ignored: quality appeared higher when evaluating the main stream of the Nakdong river using TOC instead of COD. Therefore, there remains a need to review water quality ratings based on TOC; continuous monitoring of COD is also required. In addition, the cause of the difference should be clearly identified to help assess artificial sources of pollution and natural factors affecting organic matter. Water management of the Nakdong river will then be possible using the water quality rating.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.39-49
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• 2023

Soil contaminants measured and managed in Korea include those of geologic origin such as arsenic, cadmium, copper, lead, zinc, nickel, mercury, and fluoride. This study identifies the distribution of these contaminants using GIS modeling to analyze the spatial probability of soil contamination originating from geology. The modeling found that cadmium, copper, lead, nickel, and mercury often exceed the regulated standard by <1%. Concentrations of arsenic and zinc greatly exceeded the standard in the vicinity of mines and industrial complexes: mining and industry seemed to have substantial effects on the concentrations of these metals. Although fluoride was sampled at the lowest number of points, its frequency of exceeding the standard was the highest. No obvious source of artificial contamination has been identified, and fluoride's distribution characteristics showed continuity over a wide area, suggesting a strong correlation between geological characteristics and fluoride concentration. The highest frequencies of fluoride exceeding the standard were in Jurassic granite (40.00%) and Precambrian banded gneiss (34.12%). As these rocks contributed to the formation of soil through their weathering, high fluoride concentrations can be expected in soil in areas where these rocks are distributed.

• Journal of Industrial Convergence
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• v.20 no.11
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• pp.149-155
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• 2022

This study conducted a descriptive research to compare the degree of patient safety culture awareness among general hospitals and long-term care hospital nurses. The subjects of this study were 150 nurses who worked for more than 6 months at 2 general hospitals and 4 long-term care hospitals located in 3 cities, the data has collected from October to December 2021. To Measure patient safety culture, the patient safety culture measurement tool developed by Soon Gyo Lee was used. Data were analyzed by 𝑥²-test, ANOVA, and t-test using SPSS 20.0 program. As a result of the study, the variables with high patient safety culture were the nurse's age(F=44.17, p=.000), clinical career(F=62.86, p=.000), and current workplace career(F=26.27, p=.000). Among the subdomains of patient safety culture, leadership(t=2.07, p= .040) and patient safety priorities(t=2.18, p=.031) were found to be higher in long-term care hospital nurses than general hospital nurses. Based on this result, we expected that it can be used as data in developing programs to raise the level of patient safety culture in hospitals and long-term care hospitals.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.27-34
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• 2023

In this study, various plant-based biomass are recycled into carbon materials to employ as anode materials for lithium-ion batteries. Firstly, various biomass of rice husk, chestnut, tea bag, and coffee ground are collected, washed, and ground. The carbonization process is followed under a nitrogen atmosphere at 850℃. The morphological and chemical properties of materials are investigated using FE-SEM, EDS, and FT-IR to compare the characteristic differences between various biomass. It is noticeable that biomass-derived carbon materials vary in shape and degree of carbonization depending on their precursor materials. These materials are applied as anode materials to measure the electrochemical performance. The specific capacities of rice husk-, chetnut-, tea bag-, and coffee ground-derived carbon materials are evaluated as 65.8, 80.2, 90.6, and 104.7 mAh g^-1 at 0.2C. Notably, coffee ground-based carbon exhibited the highest specific capacity owing to the difference in elemental composition and the degree of carbonization. Conclusively, this study suggests the possibility of utilizing as energy storage devices by employing various plant-based biomass into active materials for anodes.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.5-13
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• 2023

In this study, a comparative study is conducted on the synthesis methods for silica nanoparticle employing the silicon sludge waste generated from the semiconductor manufacturing processes. Specifically, acid-washed silicon sludge wastes with no impurities are employed as the precursors of sol-gel and hydrothermal methods for silica nanoparticles preparation. The morphologies and properties of silica nanoparticles synthesized via two synthetic methods are examined by various analysis methods. As a result, silica nanoparticles from the sol-gel method are fabricated with high purity and uniform shape, while the hydrothermal method exhibits advantages in yield and ease of synthetic process. This comparative study offers detailed experimental results on the two synthetic methods for silica nanoparticle synthesis, which may contribute to the establishment of manufacturing high-value materials using the by-products generated in the semiconductor process.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.35-41
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• 2023

In this study, silicon sludge generated in semiconductor manufacturing process is recycled and applied as materials for pigments and paints. In detail, metallic impurities are removed from silicon sludge to obtain plate-like silicon sludge powder (SW-sludge), which is then coated with titanium dioxide via sol-gel method (TCS-sludge). SW-sludge and TCS-sludge are dispersed in hydrophilic transparent varnish and sprayed onto glass substrates to observe the possibility for the application as materials for pigments and paints. Notably, the applicability of TCS-sludge-based paint is improved compared to SW-sludge-based paint after the titanium dioxide coating. Moreover, the color of TCS-sludge-based paint turns into white. Accordingly, it is confirmed that the applicability and hydrophilicity are improved by the presence of outer titanium dioxide layer. In this regard, it is expected that the recycled TCS-sludge may be a future material for the application as pigments and paints.

• (The) Research of the performance art and culture
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• no.41
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• pp.321-352
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• 2020

Donghaean Byeolsingut itself reflects the ideals and dreams of seaside life. Imagination and interest in water are fully reflected in Donghaean Byeolsingut as a living in a seaside town. For the beach people, water is the foundation of life and the object of fear. It is the water of life and the water of death. It projects the whole process of life into the imagination created by the world encompassed by the sea. The beach's imagination is an existential insight into the whole process of life and a reflection of existential agony. At Poongeoje, the villagers hope for a specific blessing from God. People are free only when God's retribution comes down. The villagers feel free because of the virtue of the shaman's blessing. Individual trauma is experienced to a certain extent by gaining mental freedom. It can be said that the state of aesthetic pleasure experienced by creating an art work by itself and the nature of aesthetic pleasure experienced through Pungeoje and Byeolsingut are not different. The prototype of Poongeoje is a free spirit, and a religious aesthetic to strengthen the free spirit is the core of the aesthetic.

• (The) Research of the performance art and culture
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• no.42
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• pp.291-319
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• 2021

In this paper, I looked for the parts where laughter appeared in the Mundoong, Yangban, Yeongno, and Grandfather and Grandmother of Tongyeong Ogwangdae and Dongrae Yaryu, and investigated the meaning of those parts. Laughter in mask play has made him more tolerant of human injustice and foolishness. I softened the critical content and naturally revealed what I thought should be hidden. Through a short and noisy plot, the opposing forces, the inner conflict of the Mundoong, Yangban, Yeongno, and Grandfather and Grandmother were shown in a realistic and realistic way. The worldview that creates the structure of realism is typically skeptical and ironic, and the worldview that creates the comical structure related to laughter aims for the ultimate emergence of a new order based on unity and harmony. Masking is thought to be a work in the stage of moving from the latter to the former. Therefore, it is judged that laughter in mask play served as an important medium for Korean art thought to have a realist view of the world. This is because various expression methods that induce laughter are working to reveal negativity, reveal the illusion of contemporary values, and naturally expose restraint and taboo suppression. In laughter, there is a path that transforms perception by fusing several elements. There was realism at the end of the pathway to new perception.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.1
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• pp.41-52
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• 2023

Background: Bulgarian split squat (BSS) is beneficial to improve dynamic balance ability and muscle activity of lower extremities, however its effects have not been fully investigated. Therefore, this study aimed to compare changes in dynamic balance ability and muscle properties according to various modifications of BSS exercises. Methods: Thirty healthy male volunteers participated in this study, and they were randomly divided into three different groups. The subjects performed the BSS exercise either on a stable surface with the eyes opened (n=10) or eyes closed (n=10), and on an unstable support plane with eyes opened (n=10) conditions, respectively. Dynamic balance ability was measured via Biodex balance system under the eyes-opened and closed conditions. Additionally, muscle properties of the rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL) were evaluated. Results: Dynamic balance ability did not show the significant differences among the groups that performed the BSS exercises. However, in the Unstable group, there were significant differences in the overall stability index and anterior posterior stability index under the eyes-closed condition between pre-exercise and post-exercise. In comparison of muscle properties according to the groups, RF muscle showed a significant difference in amount of change of elasticity (p=.038). Additionally, there were significant changes in post measurements of VM muscle tone (p=.016), stiffness (p=.012) and elasticity (p=.002). VL muscle, however had no significant differences in muscle properties. Conclusion: These results indicate that BSS exercises could induce the alteration of RF and VM muscle properties, in particular VM muscle which is susceptible to weakness. Thus, BSS could be applied in various ways as an effective rehabilitation exercise.