• Journal of the Korean Electrochemical Society
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• v.13 no.2
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• pp.116-122
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• 2010

A $Cu_3Si$ film electrode is obtained by Si deposition on a Cu foil using DC magnetron sputtering, which is followed by annealing at $800^{\circ}C$ for 10 h. The Si component in $Cu_3Si$ is inactive for lithiation at ambient temperature. The linear sweep thermammetry (LSTA) and galvano-static charge/discharge cycling, however, consistently illustrate that $Cu_3Si$ becomes active for the conversion-type lithiation reaction at elevated temperatures (> $85^{\circ}C$). The $Cu_3Si$ electrode that is short-circuited with Li metal for one week is converted to a mixture of $Li_{21}Si_5$ and metallic Cu, implying that the Li-Si alloy phase generated at 0.0 V (vs. Li/$Li^+$) at the quasi-equilibrium condition is the most Li-rich $Li_{21}Si_5$. However, the lithiation is not extended to this phase in the constant-current charging (transient or dynamic condition). Upon de-lithiation, the metallic Cu and Si react to be restored back to $Cu_3Si$. The $Cu_3Si$ electrode shows a better cycle performance than an amorphous Si electrode at $120^{\circ}C$, which can be ascribed to the favorable roles provided by the Cu component in $Cu_3Si$. The inactive element (Cu) plays as a buffer against the volume change of Si component, which can minimize the electrode failure by suppressing the detachment of Si from the Cu substrate.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.3
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• pp.59-71
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• 2015

Purpose : This study examines the effect of vibration exercise grafting PNF patterns for 6 weeks on upper body stability and equilibrium for seniors having fifteen or over of MMSE-K. Method : A total of 10 senior citizens participated in this study. Each participant performed PNF patterned exercises using vibration sports equipment for 30 minutes, once static a week, for six weeks. We measured trunk stability and balance degree before and after the six-week exercise program. Motor Assessment Scale (MAS) was used to measure trunk stability, while Functional Reach Test (FRT) and Timed Up and Go (TUG) was used to measure balance degree. The collected data was processed using paired t-test to confirm the difference between pre-program conditions and post-program conditions. Results: The results of our study show that post-program trunk stability measurements increased when compared to pre-program data; however, this increase was not statistically significant. pre and post-measurements for satatic balance and dynamic balance were statistically unchanged. Conclusion: Due to limitations in the number of participants, the procedural design of this experiment, and the limited amount of time participants actually controlled, this study failed to produce statistically significant results. However, further study should be conducted using a systematically implemented exercise program to show support for exercising with flexi-bar as an effective program for the elderly.

• Clean Technology
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• v.26 no.3
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• pp.186-195
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• 2020

The isothermal adsorption, dynamic, and thermodynamic parameters of Acid black (AB) and Quinoline yellow (QY) adsorption by activated carbon were investigated using the initial concentration, contact time, temperature, and pH of the dyes as adsorption parameters. The adsorption equilibrium data fits the Freundlich isothermal adsorption model, and the calculated Freundlich separation factor values found that activated carbon can effectively remove AB and QY. Comparing the kinetic data showed that the pseudo second order model was within 10% error in the adsorption process. The intraparticle diffusion equation results were divided into two straight lines. Since the slope of the intraparticle diffusion line was smaller than the slope of the boundary layer diffusion line, it was confirmed that intraparticle diffusion was the rate-controlling step. The thermodynamic experiments indicated that the activation energies of AB and QY were 19.87 kJ mol^-1 and 14.17 kJ mol^-1, which corresponded with the physical adsorption process (5 ~ 40 kJ mol^-1). The adsorption reaction was spontaneous because the free energy change in the adsorption of AB and QY by activated carbon was negative from 298 to 318 K. As the temperature increased, the free energy value decreased resulting in higher spontaneity. Adsorption of AB and QY by activated carbon showed the highest adsorption removal rate at pH 3 due to the effect of anions generated by dissociation. The adsorption mechanism was electrostatic attraction.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.151-165
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• 2019

In this study, the four types of improvement methods (increase self weight and reducing sliding force etc.) were proposed depending on install location with compaction grouting to improve seismic performance of existing port structure and optimal methods by analyzing the effects of improvement (stability, constructability and economy) by theoretical and numerical methods. From the dynamic time history analysis for artificial seismic waves, the results indicated that the horizontal displacement after improvement decreased compared to before improvement, however the displacement reduction effect among improvement methods was not significantly different. Slope stability based on the strength reduction method and the limit equilibrium analysis method, it is confirmed that the passive pile method is more safe than other methods. It is due to the shear strength at the failure surface is increased. In addition, the analysis of constructability and economy showed that the reduction of earth pressure method (type 02) and the passive pile method (type 03) are excellent. However, in the case of the passive pile method is concerned that there is a shortage of design cases and the efficiency can be reduced depend on various constraints such as ground conditions.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.1-11
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• 2001

The geological characteristics of Korea are that we can encounter the rock layer only after 10m of excavation, methods to presume the rock pressure distribution of the rock layer is urgently needed. When using the existing empiric science of Terzaghi-Peck, Tschebotarioff to measure the rock pressure of the rock layer, underestimate the real strength because of the cohesion is ignored. Therefore calculating the horizontal sliding force of wedge block, which includes the dips and shear strength of discontinuities and surcharge load etc., think to be to getting a closer rock stress of the real rock pressure acting upon the earth structure in rock mass. This research use Coulomb soil pressure theory assuming that the backfill soil will yield wedge failure when it has cohesion, applying Prakash-Saran(l963), and then it uses equilibrium of force and shear strength $\tau$=c+$\sigma$tan $\Phi$ of the cliscontinuities. Analyzing shear strength and dips of cliscontinuities using calculated theory according to the status of discontinuities aperture, we were able to find out that because the cohesion and friction angle of the rock layer itself is large enough, how the dip directions and dips facing the excavation face is the only factor deciding whether or not the rock stress is applied. The evaluated theory of this research should be strictly estimated, so that the many parameters such as c, $\Phi$value, types and structures of rock class, excessive lateral pressure, dynamic load, earthquake, needed later when calculating shear strength of discontinuities and especially the ground water effect acting on rock layer should be coumpted with many measuring data achieve at the insite to study the application.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.278-282
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• 2018

The development of treatment technologies for recycling waste woods generated from tree pruning is required in Gangwon province forest. In this study, according to adsorption experiments using three types (Larix kaemoferi, Juniperus chinensis, Pinus densiflora) of waste woods, Juniperus chinensis as a biosorbent showing an excellent removal ability was selected for the removal of methylene blue in an aqueous phase. When 0.4 g/100 mL of Juniperus chinensis was used to improve the removal efficiency of methylene blue for 4 h, each 100, 200 and 300 mg/L of methylene blue dissolved in the aqueous phase were removed to 98, 93, and 81%, respectively. The adsorption equilibrium data obtained by changing adsorbent concentrations was found to be more consistent with the Langmuir than the Freundlich equation. In addition, based on dynamic experiments by changing the methylene blue concentration, the biosorption kinetics equation was more suitable for a pseudo-second order model. In order to enhance the removal capability of highly concentrated methylene blue, 300 and 400 mg/L of methylene blue were operated for 4 h under 210 rpm of agitation velocity and removal efficiencies were 92 and 76%, respectively. Consequently, these experimental results can be effectively utilized as a new biosorption technology for economically treating methylene blue dissolved in an aqueous phase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.303-311
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• 2020

The acreage of tangerines in the U.S. sharply rose from 19,000 ha in 2009 to 27,000 ha in 2016, an increase of 42% in 7 years. Considering the recent surge in tangerine exports to Japan, the export volume of 6-7 thousand tons is highly likely to increase in the future. Therefore, the purpose of this study was to analyze the economic impact of U.S. tangerine imports on the Korean citrus industry under various scenarios. In order to examine the possibility of imports of U.S. tangerines, the unit price of U.S. exports to Japan was used since U.S. tangerines are not imported to South Korea. Citrus fruits are divided into field citrus, house citrus, and late-maturing citrus (including winter season citrus) based on the cultivation method and variety used to analyze. Considering both the field and house seasons, the import volume of U.S. tangerines can be expected to rise from roughly 4,700 tons in 2021 to 10,000 tons in 2027. Imports of U.S. tangerines may be pushed up or delayed depending not only on the harvest method and quality of domestic field and house citrus but also on the harvest of U.S. tangerines. However, it is necessary to note that tangerines could be imported after 2021, when the tariff rate on U.S. tangerines will fall below 50%.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.109-118
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• 1993

Development process of agricultural technology has been studied with a case study of Korean agriculture. Technological is considered as a transformer of inputs into outputs and hence technological appropriateness, an important aspect of agricultural development strategies, is considered as a dynamic concepts. Considering the concept of agricultural system as a delivery system for providing essential materials and services to producers and consumers, it has been divided into two major groups of dimensions vis. external challenge dimensions and internal response dimensions. Market, investment and agro-ecosystem constitute the external challenge dimensions : whereas trade , technology as well as production and resources allocation constitute internal response dimensions. The system manager is responsible for maintaining equilibrium in the mentioned six sub-systems. Two kinds of alternatives paths of technological development viz. land saving technology and labour saving technolog have been studied. Technology is considered as a combination of four basic components viz. facilities, abilities, facts and frameworks. Adoption of innovation in agriculture depends on profitability, awareness, risk aversion, financial capacity, institutional infrastructure, availability of physical inputs and adaptability to the local conditions. For a cast study of Korea, changes in the agricultural system through external challenge dimensions are investigated. The impacts of industrialization on agro-ecosystem reported are shift of labour from the agricultural sector to non-agricultural sectors and continuously increasing demand of farm the agricultural sector to non-agricultural sectors accompanied by increase in land prices. The impacts on the commodity market discussed are shift in demand from rice, barley and other cereals to meat , dairy products and vegetables : and increasing in supply capacity of agricultural inputs. The process of agricultural development from 1962 to 19 1 9 (i.e. from start of the first to the end of the sixth five year plan) are also discussed in details with several policy measures taken. The trend of agricultural income and productivity are also analyzed. The main cause of increase in the agricultural income is considered as increase in labour productivity. The study revealed that during the span of 1965-88, holding size has not changed significantly, but both the land and labour productivity increased and so did the agricultural income. R&D activities in Korea have changed over time in three stages vix. import of improved technology, localization by adaptive research and technological mastery. For the new technology to be made affordable to farmers, policy measures like fertilizer and food grain exchange system, dual price system in rice and barely and loan for machinery were strengthened.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.9
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• pp.641-647
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• 2014

In this study, sludge waste which has a difficulty in treating it was used to manufacture a fiber type of biosorbent. To solve the problems such as the release of organic pollutants and the difficulty in separating solid from treated water, entrapment method using Ca-alginate was used to immobilize sludge waste. Considering ease of manufacture as well as improvement of adsorptive ability, the biosorbent was manufactured in the form of fiber type. Optimum immobilization condition for minimizing the amount of alginate used and maximizing the performance of biosorbent was determined to be 10 g/L alginate concentration, 40 g/L sludge concentration, and 0.3-0.4 mm fiber diameter. The maximum Cd(II) uptake of the biosorbent was 60.73 mg/g. Pseudo-second-order kinetic model and Langmuir isotherm model adequately described the dynamic and equilibrium behaviors of Cd(II) biosorption onto the biosorbent, respectively. In conclusion, sludge waste generated from wastewater treatment process is a cheap raw material for the manufacture of biosorbent which can be used to remove toxic heavy metals from industrial wastewaters efficiently.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.387-397
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• 2019

The purpose of this study is to analyze the relationship between health related physical fitness, cognitive function, depression and quality of life variables of elderly people in a comprehensive way based on quantitative evaluation. The subjects of this study were 385 people who voluntarily participated in the elderly welfare center in Gyeonggi and Seoul the elderly people. As for the data collection methods, were measured the characteristics, depression and quality of life, cognitive function questionnaires along with measures of lower and upper body strength, dynamic equilibrium and agility, total endurance and grip strength. As a result, the first was a statistically significant correlation between integrated health of the elderly, cognitive function, quality of life and depression. Second, the analysis of cognitive function, elderly integrated health, quality of life, and depression revealed statistical significance among all variables. Third, there was the partial intervention effect of function in the quality of life and depression of the elderly.