• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.49-57
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• 2019

Purpose: This study aimed to investigate the application of temperature to balance the training by observing the effect of sensory changes in the foot sole area on dynamic equilibrium ability through change in the sole temperature. Methods: Participants (n=49), who were selected as a certain standard, applied cold and hot packs for ten minutes at two-week intervals, and the laboratory's internal temperature was maintained at $25^{\circ}C$. The subjects were measured before and after the cold and hot applications in the stable condition with bare feet. Before each experiment applied the cold and hot packs, the balance ability of the ordinary temperature was measured once by conducting a limit of stability test using Biorescue, and the changes in balance ability were observed by measuring once after applying the temperature to the foot sole by means of the ice pack and the hot pack. Results: The results of the dynamic balance test, both before and after the temperature application, were compared, and it was confirmed that the moving area before and after cold application decreased significantly, and the moving area before and after application was not significantly different. The mean of pre-post area differences was found to have decreased at a statistically significant rate in the forward, backward, rightward, leftward, and total areas for the group that received the cold application compared to the group that received the hot application. Conclusion: These findings showed that cold application to the foot sole decreased dynamic balance. There was no significant difference in the dynamic balance ability both before and after the hot application to the foot sole, so it is difficult to conclude that the hot application affected dynamic balance.

• Advances in nano research
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• v.7 no.5
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• pp.293-310
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• 2019

In this paper, thermal-buckling behavior of the functionally graded (FG) nanocomposite plates reinforced with graphene oxide powder (GOP) is studied under three types of thermal loading once the plate is supposed to be rested on a two-parameter elastic foundation. The effective material properties of the nanocomposite plate are considered to be graded continuously through the thickness according to the Halpin-Tsai micromechanical scheme. Four types of GOPs' distribution namely uniform (U), X, V and O, are considered in a comparative way in order to find out the most efficient model of GOPs' distribution for the purpose of improving the stability limit of the structure. The governing equations of the plate have been derived based on a refined higher-order shear deformation plate theory incorporated with Hamilton's principle and solved analytically via Navier's solution for a simply supported GOP reinforced (GOPR) nanocomposite plate. Some new results are obtained by applying different thermal loadings to the plate according to the GOPs' negative coefficient of thermal expansion and considering both Winkler-type and Pasternak-type foundation models. Besides, detailed parametric studies have been carried out to reveal the influences of the different types of thermal loading, weight fraction of GOP, aspect and length-to-thickness ratios, distribution type, elastic foundation constants and so on, on the critical buckling load of nanocomposite plates. Moreover, the effects of thermal loadings with various types of temperature rise are investigated comparatively according to the graphical results. It is explicitly shown that the buckling behavior of an FG nanocomposite plate is significantly influenced by these effects.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.211-223
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• 2021

Purpose : The purpose of this study was to examine the effect of task-oriented circuit training using unstable support surface on balance, gait ability, and balance confidence in subacute stroke patients. Methods : Forty-five patients with subacute stroke were randomly divided into the three following groups of 15: 1) TOCT-US group; task-oriented circuit training using unstable surface (experimental group 1), 2) TOCT-SS group; task-oriented circuit training using stable surface (experimental group 2), and 3) CON group; conventional physical therapy (control group). All patients participated in one of the three training programs for 6 weeks, 30 minutes per session, 3 times per week. Patients' balance ability was assessed using the BT-4, BBS (berg balance scale), TUG (time up and go test), and LOS (limit of stability). Gait speed was measured to examine gait ability. K-ABC (activities-specific balance confidence scale) was also used to assess the level of patients' confidence in daily activities. Results : After the intervention, the sway area in experimental groups 1 and 2 decreased, but that in the control group increased. Experimental group 1 showed significant improvement compared with experimental group 2 and the control group. BBS, TUG, and LOS scores of experimental group 1 were significantly improved compared with those of experimental group 2 and the control group. Also, gait speed significantly improved in experimental group 1 compared with experimental group 2 and the control group. Experimental groups 1 and 2 showed significant improvement in K-ABC scores after training. Conclusion : Patients with subacute stroke had significantly improved balance, gait, and level of confidence in performing activities of daily living following task-oriented circuit training using the unstable surface. This indicates that task-oriented circuit training using unstable surfaces can be an effective treatment method for the recovery of balance and gait in subacute stroke patients.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.653-660
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• 2021

Renewable energy resources are rapidly becoming an integral part of electricity generation portfolios around the world due to declining costs, government subsidies, and corporate sustainability goal. Interacting wind, solar, and load forecast errors can create significant unpredictable impacts on the distribution system, feeder congestion, voltage standard and reactive power stability margins. These impacts will be increasing with the increasing penetration levels of variable renewable generation in the power systems. There is a limit to the maximum amount of renewable energy sources that can be connected in a distribution feeder by the connection rule of transmission & distribution facility in Korea. This study represents the decision plans of hosting capacity for distribution feeders without the need for significant upgrades to the existing transmission infrastructure. Especially, the paper suggests and discusses the hosting capacity standard of feeder cables and minimum load calculation of distribution feeders.

• Computers and Concrete
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• v.26 no.6
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• pp.483-495
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• 2020

Dams are vital infrastructures that are expected to maintain their stability during seismic excitations. Accordingly, cemented material dams are an emerging type, which are being increasingly used around the world owing to benefiting from advantages of both earth-fill and concrete gravity dams, which should be designed safely when subjected to strong ground motion. In the present paper, the seismic performance of a cemented sand and gravel (CSG) dam is assessed using incremental dynamic analysis (IDA) method by accounting for two failure modes of tension cracking and base joint sliding considering the dam-reservoir-foundation interactions. To take the seismic uncertainties into account, the dam is analyzed under a suite of ground motion records and then, the effect of friction angle for base sliding as well as deformability of the foundation are investigated on the response of dam. To carry out the analyses, the Cindere dam in Turkey is selected as a case study, and various limit states corresponding to seismic performance levels of the dam are determined aiming to estimate the seismic fragilities. Based on the results, sliding of the Cindere dam could be serious under the maximum credible earthquake (MCE). Besides, dam faces are mostly to be cracked under such level of intensity. Moreover, the results indicate that as friction angle increases, probability of sliding between dam and foundation is reduced whereas, increases tensile cracking. Lastly, it is observed that foundation stiffening increases the probability of dam sliding but, reduces the tensile damage in the dam body.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.35-43
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• 2020

Currently, cofferdams of circular cross section are widely applied as temporary facilities for the installation of bridge foundations in river/sea bridge construction in Korea. Existing caisson, sheet pile, and cell type cofferdam are widely used, but these methods take a lot of time and cost for installation and dismantling. In the case of the existing sheet pile construction method, attention is needed to secure internal and external stability because of the damage to the sheet pile due to ground penetration and difficulty in connecting element members. In this study, penetration design of circular steel pipes using suction pressure was performed on the soft ground of the west coast, and it was confirmed that penetration construction using suction pressure was possible through field tests. It was confirmed that applying the ground analysis results using the cone penetration test (CPT) to the design rather than the standard penetration test (N value) results more similar to the field test results. In addition, it was confirmed that local failure of the inside of the cofferdam was induced when a suction pressure higher than the upper limit suction pressure was applied in the silty sand.

• Journal of Electrochemical Science and Technology
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• v.13 no.1
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• pp.78-89
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• 2022

ANODE-free Li-metal batteries (AFLMBs) operating with Li of cathode material have attracted enormous attention due to their exceptional energy density originating from anode-free structure in the confined cell volume. However, uncontrolled dendritic growth of lithium on a copper current collector can limit its practical application as it causes fatal issues for stable cycling such as dead Li formation, unstable solid electrolyte interphase, electrolyte exhaustion, and internal short-circuit. To overcome this limitation, here, we report a novel dual-salt electrolyte comprising of 0.2 M LiPF₆ + 3.8 M lithium bis(fluorosulfonyl)imide in a carbonate/ester co-solvent with 5 wt% fluoroethylene carbonate, 2 wt% vinylene carbonate, and 0.2 wt% LiNO₃ additives. Because the dual-salt electrolyte facilitates uniform/dense Li deposition on the current collector and can form robust/ionic conductive LiF-based SEI layer on the deposited Li, a Li/Li symmetrical cell exhibits improved cycling performance and low polarization for over 200 h operation. Furthermore, the anode-free LiFePO₄/Cu cells in the carbonate electrolyte shows significantly enhanced cycling stability compared to the counterparts consisting of different salt ratios. This study shows an importance of electrolyte design guiding uniform Li deposition and forming stable SEI layer for AFLMBs.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.206-216
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• 2022

BACKGROUND: Dithiocarbamate fungicide propineb can be analyzed quantitatively by derivatization reaction followed by HPLC/UVD, which has high reproducibility and stability. However, the presence of high protein in soybeans and peas affects the derivatization process resulting in extremely low recoveries. Therefore, this study was conducted to improve the analytical method for analysis of propineb in soybeans and peas by applying a deproteinization process using chloroform-gel method. METHODS AND RESULTS: The deproteinization process was carried out up to 6 times for soybeans and 5 times for peas using 50 mL chloroform. After 4 times of deproteinization process followed by a derivatization reaction with methyl iodide, the recovery yields of propineb in both pulses were >90%. However, the recovery yield tended to decrease when the deproteinization process was performed more than 5 times. The method limit of quantification (LOQ) was 0.04 mg/L. The recovery conducted in triplicate at 10 times and 50 times of the LOQ ranged from 87.2 to 95.0 % with a coefficient of variation <10%. CONCLUSION(S): This study confirmed that 4 times of deproteinization process using the chloroform-gel method was effective when derivatizing and analyzing dithiocarbamate fungicides in pulses with high protein content. However, depending on the initial protein content present in the pulses, there was a difference in the recovery: the lower the protein content, the higher the recovery rate of propineb. It is expected that the method proposed in this study could be applied to remove high content of protein as analytical interference substance from agricultural samples.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.93-98
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• 2021

In Europe, it is necessary to fulfil the type certification criteria by the European Aviation Safety Agency (EASA) when developing an aircraft engine. According to type certification criteria, a 150 hours endurance test should be performed to verify the stability of the engine structure under the engine's operating limit conditions. The type certification criteria for the 150 hour endurance test are specified in JAR-E, which is the EASA type certification. Currently, the Arriel 2L2 engine is being developed in cooperation with a foreign manufacturer, and a 150 hours endurance test was performed. In this study, a 150 hours endurance test procedure is conducted in consideration of the operation characteristics of the currently developed engine.

• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.19-33
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• 2022

Newmark's sliding block analysis is the most commonly used method for predicting earthquake-induced permanent displacement of embankment slopes. Additionally, it yields the amount of slip circle sliding using the limit equilibrium theory. Thus, permanent displacement does not occur until the seismic load exceeds the yield acceleration, which induces sliding of the slip circle. The evolution of Newmark's sliding block analysis has been made by introducing the numerical seismic response analysis results since it was introduced. This study compares seismic performance evaluation results for the example enclosure dam section with the analysis methods. As a result, earthquake-induced permanent displacement using Newmark's sliding block analysis did not occur for the enclosure dam, indicating a high safety factor. However, nonlinear response history analysis gave reasonable results.