• Korean Journal of Remote Sensing
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• v.40 no.1
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• pp.81-91
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• 2024

Electrical energy is a key source of energy for modern civilization, and changes in electricity generation and consumption are closely related to industry and life in general. In this study, we identified the correlation between electricity generation and nighttime light values in South Korea and used it to predict monthly electricity generation trends in North Korea. The results of the study showed a low Pearson correlation coefficient of 0.34 between nighttime light and electricity generation in Seoul, but a high Pearson correlation coefficient of 0.79 between weighting for Seoul case nighttime light values and electricity generation using monthly average temperature. Using nighttime light values weighting for Seoul case by the average monthly temperature in Pyongyang to predict the monthly power generation trend in North Korea, we found that the month-on-month power generation increase in December 2022 was about 60% higher than the month-on-month power generation increase in December 2020 and 2021. The results of this study are expected to help predict monthly electricity generation trends in regions where monthly electricity generation data does not exist, making it difficult to identify timely industry trends.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.20-34
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• 2023

Single or multi-layered two-dimensional (2D) materials, with thicknesses in the order of a few nanometers, have garnered substantial attention across diverse research domains owing to their distinct properties, including electrical conductivity, flexibility, and optical transparency. These materials are frequently subjected to repetitive mechanical actions in applications like electronic skin (E-Skin) and smart textiles. Moreover, they are often exposed to external factors like temperature, humidity, and pressure, which can lead to a deterioration in component durability and lifespan. Consequently, significant research efforts are directed towards developing self-healing properties in these components. Notably, recent investigations have revealed promising outcomes in the field of self-healing composite materials, with Ti₃Ci₂Ti_x MXene being a prominent component among the myriad of available 2D materials. In this paper, we aim to introduce various synthesis methods and characteristics of Ti₃Ci₂Ti_x MXene, followed by an exploration of self-healing application technologies based on Ti₃Ci₂Ti_x MXene.

• Journal of Industrial Convergence
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• v.21 no.10
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• pp.57-63
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• 2023

This study aims to elucidate the effect of glycyrrhizic acid on smooth muscle contraction and to determine the detailed mechanism incorporated. We hypothesized that glycyrrhizic acid played a role in the agonist-sensitive management of smooth muscle contraction. Stripped smooth muscles of Sprague-Dawley rats were prepared in organ baths and isometric tensions were converted, stored and analyzed by using isometric transducers, a physiograph and one way ANOVA. Interestingly, glycyrrhizic acid attenuated the thick filament regulating agonist (fluoride or thromboxane mimetic)-sensitive contraction (p=0.113, 0.008, 0.004 (Student's t-test), p=0.113, 0.008, 0.004 (One way ANOVA) at 0.01, 0.03, 0.1 mM fluoride, and p=0.156, 0.004, 0.003 (Student's t-test), p=0.156, 0.004, 0.003 (One way ANOVA) at 0.01, 0.03, 0.1 mM thromboxane mimetic) and did not attenuate the thin filament regulating agonist (phorbol ester)-induced contraction (p=0.392, 0.086, 0.065 (Student's t-test), p=0.392, 0.086, 0.065 (One way ANOVA) at 0.01, 0.03, 0.1 mM phorbol ester). It is suggesting that endothelial EDRF (NO) synthesis and accessory pathways besides endothelial EDRF (NO) synthesis such as ROCK restriction might be incorporated in the glycyrrhizic acid-induced modulation of smooth muscle contraction inhibiting acto-myosin interaction.

• Korean Journal of Acupuncture
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• v.40 no.4
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• pp.184-193
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• 2023

Objectives : The purpose of this study is to understand the temperature characteristics depending on the thickness and material of the needle used with the Electronic Warm Acupuncture Device (EWAD). Methods : We controlled experimental environment and measured temperature changes of a silicon phantom in which K-type thermocouples were inserted at depths of 2, 7 mm. EWAD perfomed with acupuncture needles of various thicknesses (0.25×60 mm, 0.40×60 mm, and 0.50×60 mm) and materials (Gold 0.40×50 mm). We set non-needle (only heated with EWAD skin heater) group as a control group. Results : The maximum temperature and temperature changes of 0.40 mm, 0.50 mm needle group were significantly higher than the non-needle group. The highest temperature range in all needle groups was 0.50 mm needle group (41.44±0.31℃). However, the 0.25 mm needle group was not significantly different from the non-needle group. Maximum temperature of gold needle group was significantly higher than stainless steel needle group. Temperature changes of gold needle group were higher than stainless steel group at the depth of 7 mm. Conclusions : It was found that needle thickness and material of acupuncture had an effect on the temperature of the EWAD. When performing EWAD treatment, consideration of thickness and material of acupuncture is needed. Future research is needed using phantoms that can reflect actual clinical situations and better mimic the human body.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.831-846
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• 2023

The Jucheon-Pyeongchang area in the northwestern Taebaeksan Zone of the Okcheon fold-thrust belt preserved several thrust faults placing the Precambrian basement granite gneisses of the Gyeonggi Massif on top of the Early Paleozoic Joseon Supergroup and the age-unknown Bangrim Group. Especially, the thrust faults in the study area show the closed-loop patterns on the map view, showing older allochthonous strata surrounded by younger autochthonous or para-autochthonous strata. These basement-involved thrusts including Klippes will provide important information on the hinterland portion of the fold-thrust belt. For defining Klippe geometry in the thrust fault terrains of the Jucheon-Pyeongchang area by older on younger relationship, the stratigraphic position of the age-unknown Bangrim Group should be determined. The Middle Cambrian maximum depositional age by the detrital zircon SHRIMP U-Pb method from this study, together with field relations and previous research results suggest that the Bangrim Group overlies the Precambrian basement rocks by nonconformity and underlies the Cambrian Yangdeok Group (Jangsan and Myobong formations). The structural geometric interpretation of the Pyeongchang area based on newly defined stratigraphy indicates that the Wungyori and Barngrim thrusts are the same folded thrust, and can be interpreted as a Klippe, having Precambrian hanging wall granite gneisses surrounded by younger Cambrian strata of the Joseon Supergroup and the Bangrim Group. Further detailed structural studies on the Jucheon-Pyeongchang area can give crucial insights into the basement-involved deformation during the structural evolution of the Okcheon Belt.

• Particle and aerosol research
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• v.19 no.3
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• pp.53-62
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• 2023

This study compared the collection efficiency of a two-stage electrostatic precipitator (ESP) with a lightweight PET film-coated carbon electrode collector plate, depending on the relative humidity of the exhaust gas and the applied voltage to the pre-charger. It was confirmed that the onset voltage at which corona discharge occurs decreases and the discharge current decreases at the same voltage as the relative humidity increases. On the other hand, even though there was almost no change in the diameter of the particles generated depending on the relative humidity, the efficiency was higher at the same voltage as the relative humidity increased. In addition, by applying a two-stage ESP structure, the collection efficiency was higher than that of a single-stage electrostatic precipitator under the same conditions. The ESP using the carbon electrode coated with PET film used in this study is expected to be effective in various aspects such as weight and in the current situation where environmental regulations are rapidly tightening.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.85-85
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• 2022

영농형 태양광발전은 태양의 일사량을 전기발전과 영농에 공유하는(solar-sharing) 방식이다. 본 연구는 신재생에너지의 활용의 극대화를 위하여 추적식 영농형 태양광발전시스템을 구축하고 시설하부에서 일정 기간 재배중인 작물의 하부 환경과 생육을 조사하여 영농형태양광 하부작물개발을 위한 기초자료를 확보하고자 하였다. 구축한 추적식 영농형 태양광발전시스템은 4열 6단의 24장 모듈(8m × 6m)을 가지며, 발전시설 중심축 기둥 간 중심간격 14m로 단일지주식 스크루 공법으로 순천대학교 부속농장 답작포(순천시 죽평리)에 설치하여 하부 환경과 하부작물의 생육을 조사하였다. 태양광발전시설 하부작물의 생육을 조사하기 위하여 순천 농협육묘장에서 벼(신동진)를 육묘하여 2022년 6월 16일 이앙하였다. 태양광발전시스템 하부 지역을 4방위 방향에 따라 강음영(중심축으로부터 1~3m), 중음영(5m), 약음영(7~9m) 구역으로 설정하여 생육을 조사한 결과, 방위에 따른 초장은 남쪽에서 음영간 차이가 상대적으로 낮게 나타났으며, 1번기 태양광 발전시설에 의하여 음영이 중첩된 2번기 시설의 동쪽에서 대조구 대비 초장이 상대적으로 낮은 경향을 나타내었다. 음영강도에 따른 초장은 대체로 강음영구에서 낮게 나타났으며, 약음영구로 갈수록 높게 나타났다. 엽수는 방위에 따라서, 그리고 음영의 강도에 따른 차이가 초장에 비하여 작게 나타났다. 출수기의 경우 방위별로는 남쪽에서 음영별 차이가 작게 나타났으며, 음영강도에 따라서 차이를 보였다. 또한 태양광시설 하부에 데이터수집장치(Model 1650, Spctrum Technonogies, USA)를 설치하여 음영에 따른 토양전도도, 토양함수량, 토양온도, par light 등 생육환경을 조사, 비교하였다.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.63-69
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• 2022

Vanadium dioxide shows a unique and interesting property of metal-insulator transition, which has attracted great attention from the viewpoints of fundamental materials science and industrial applications. In this study, the effect of Mg and W addition on the metal-insulator transition of VO₂ were investigated for the bulk materials that are prepared by spark plasma sintering. The X-ray diffraction analysis of the sintered specimens revealed that the lattice parameters barely change, and the secondary phases are present. The transition temperature of MIT appears in the range of 64.2-64.6℃, regardless of the impurity element and content. On the other hand, the addition of Mg and W alters the electrical conductivity, i.e., the electrical conductivity increases by a factor of up to 2.4 or decrease by a factor of up to 57.4 depending on the impurity type and its content. The thermal conductivity showed the values of 1.8~2.5 W/m·K below the transition temperature, and the values of 1.9~2.8 W/m·K above the transition temperature. These changes in electrical and thermal conductivities can be attributed to the combination of the change in charge carrier density, the impurities as scattering centers, and the change in microstructures.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.21-27
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• 2022

Flexible pressure sensor was developed using low-cost conductive graphite as printed electronics. Flexible pressure sensors are attracting attention as materials to be used in future industries such as medical, games, and AI. As a result of evaluating various electromechanical properties of the printed electrode for flexible pressure sensors, it showed a constant resistance change rate in a maximum tensile rate of 20%, 30° tension/bending, and a simple pulse test. A more appropriate matrix pattern was designed by simulating the electrodes for which this verification was completed. Utilizing the Serpentine pattern, we utilized a process that allows simultaneous fabrication and encapsulation of the matrix pattern. One side of the printed graphite electrode was O₂ plasma surface treated to increase adhesive strength, rotated 90 times, and two electrodes were made into one through a lamination process. As a result of pasting the matrix pattern prepared in this way to the wrist pulse position of the human body and proceeding with the actual measurement, a constant rate of resistance change was shown regardless of gender.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.130-137
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• 2023

By using XRF (X-ray fluorescence), this study investigates the variation of chemical properties in cement pastes at elevated temperatures. High-temperature conditions were prepared by using an electric furnace, planning a total of 11 target temperatures ranging from room temperature to 1000 ℃. A standard library of geo-quant basic was applied for the analysis of 12 elements in cement paste, including Ca, Si, Al, Fe, S, Mg, Ti, Sr, P, Mn, Zn and K. The results revealed that, as the temperature increased, the proportion of each element in the cement paste also increased. With the exception of a few elements present in extremely low amounts in the cement pastes, the variation in the composition ratio of most elements exhibited a strong correlation with temperature, with an R-squared value exceeding 0.98. In this study, cement pastes exposed to normal and high-temperature environments were compared. The authors established that the reasons for the different results in this comparison can be explained from the same perspective as when comparing raw cement with cement paste. Furthermore, this study discussed the potentially most dominant parameter when investigating the properties of cement paste using XRF.