• Korean Journal of Materials Research
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• v.6 no.8
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• pp.817-824
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• 1996

Removal of Cu impurities on Si substrates using remote H-plasma was investigated. Si substrates were intentionally contaminated by 1ppm ${CuCI}_{2}$, standard chemical solution. To determine the optimal process condition, remote H-plasma cleaning was conducted varying the parameters of rf power, cleaning time and remoteness(the distance between the center of plasma and the surface of Si substrate). After remote H-plasma cleaning was conducted, Si surfaces were analysed by TXRF(total x-ray reflection fluorescence) and AFM(atomic force microscope). The concentration of Cu impurity was reduced by more than a factor of 10 and its RMS roughness was improved by more than 30% after remote H-plasma cleaning. TXRF analysis results show that remote H-plasma cleaning is effective in eliminating Cu impurity on Si surface when it is performed under the optimal process condition. AFM analysis results also verifies that remote H-plasma cleaning makes no damage to the Si surface. The deposition mechanism of Cu impurity may be explained by the redox potential(oxidation-reduction reaction potential) theory. Based on the XPS analysis results we could draw a conclusion that Cu impurities on the Si substrate are removed together with the oxide by a "lift-off" mechanism when the chemical oxide( which forms when Cu ions are adsorbed on the Si surface) is etched off by reactive hydrogen atoms.gen atoms.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.771-782
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• 2017

This paper describes the development of a wearable robot to assist ankle power for the elderly. Previously developed wearable robots have generally used motors and gears to assist muscle power during walking. However, the combination of motor and reduction gear is heavy and has limitations on the simultaneous control of stiffness and torque due to the friction of the gear reducer unlike human muscles. Therefore, in this study, Mckibben pneumatic muscle, which is lighter, safer, and more powerful than an electric motor with gear, was used to assist ankle joint. Antagonistic actuation using a pair of pneumatic muscles assisted the power of the soleus muscles and tibialis anterior muscles used for the pitching motion of the ankle joint, and the model parameters of the antagonistic actuator were experimentally derived using a muscle test platform. To recognize the wearer's walking intention, foot load and ankle torque were calculated by measuring the pressure and the center of pressure of the foot using force and linear displacement sensors, and the stiffness and the torque of the pneumatic muscle joint were then controlled by the calculated ankle torque and foot load. Finally, the performance of the developed ankle power assistive robot was experimentally verified by measuring EMG signals during walking experiments on a treadmill.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.752-759
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• 2014

Varieties of research on turbulent-induced noise is conducted with combinations of acoustic analogy methods and computational fluid dynamic methods to analyze efficiently and accurately. Application of FW-H acoustic analogy without turbulent noise is the most popular method due to its calculation cost. In this paper, turbulent-induced noise is predicted using RANS turbulence model and permeable FW-H method. For simplicity, noise from 2D cylinder is examined using three different methods, direct method of RANS, FW-H method without turbulent noise and permeable FW-H method which can take into account of turbulent-induced noise. Turbulent noise was well predicted using permeable FW-H method with same computational cost of original FW-H method. Also, ability of permeable FW-H method to predict highly accurate turbulent-induced noise by applying adequate permeable surface is presented. The procedure to predict turbulent-induced noise using permeable FW-H is established and its usability is shown.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.1
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• pp.107-118
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• 2016

The Seoul metropolitan government announced an open design competition for reconfiguring the annex building of the National Tax Service Building site on Sejong-daero as a space for citizens to commemorate the 70th anniversary of Korea's liberation. The site, built during the Japanese colonial period, has been in use ever since. This study, as one of the entries for the competition, described the strategy and design contents by drawing the concept and main points of the design through an analysis of the historical context of the site. As the guidelines instructed to consider the value of the Sejong-daero area and the cultural heritage through a comprehensive analysis, this study specified the site as a place connecting the past, present and future. Since the foundation of the Joseon dynasty, the Korean Empire and the Japanese colonial period, Sejong-daero has been a main site for important events and activities along with the change of the city structure. Jungdong, to the rear of the site, was a place for adopting new culture during the beginnings of modern Korea, while adjacent places like Duksugung, the Anglican church, and the Seoul City Council building have also been historic urban landscapes of the historical layers of time as the city has changed. When Gojong announced the Korean Empire, the city structure was remodeled with this site as the center along with Sogong-ro, Wongudan and so forth. In this study, public interest stated in the guidelines was focused and the relevance of the road and the plaza was considered from the view of an historic urban landscape by a comprehensive analysis with Sejong-daero as the center. The restoration of public interest was to be drawn as the concept of the object site by considering the current status and the change around the site and Jungdong at the rear. Returning the site to the public is ambiguous with the relevance of the restoration of public interest and as the symbol of the idea of the Korean Empire by Gojong's announcement. The object site, having the characteristic of being returned to the public, must ensure public interest and therefore the design strategy has been established with the keywords of openness, connection and void. As a result of a review of the alternatives, a plan for a square has an 8% slope, just as the original site does, and provides ramps for convenient access for all, including the disabled and the elderly, and is connected to the grounds adjacent. No construction is allowed at the terrace square of the Anglican church level and the main square connected to the pedestrian street, so a variety of modern city utilization can be done. The value of the site at which this design is aimed shall be given back to the public with the concepts of modern democracy, independence, and the vision of Gojong by reinterpreting the space from a modern viewpoint. This study focused on the processes of establishing a main concept and strategy rather than the content of the design details, and the suggestion is meaningful in that the design for the object site with historic backgrounds and the layers of time can continue to be grown.

• Journal of The Korean Association For Science Education
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• v.40 no.6
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• pp.657-670
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• 2020

The knowledge-information-processing competency is the most essential competency in a knowledge-information-based society and is the most fundamental competency in the new problem-solving ability. Data-driven science inquiry, which emphasizes how to find and solve problems using vast amounts of data and information, is a way to cultivate the problem-solving ability in a knowledge-information-based society. Therefore, this study aims to develop a teaching-learning model and strategy for data-driven science inquiry and to verify the validity of the model in terms of knowledge information processing competency. This study is developmental research. Based on literature, the initial model and strategy were developed, and the final model and teaching strategy were completed by securing external validity through on-site application and internal validity through expert advice. The development principle of the inquiry model is the literature study on science inquiry, data science, and a statistical problem-solving model based on resource-based learning theory, which is known to be effective for the knowledge-information-processing competency and critical thinking. This model is titled "Exploratory Scientific Data Analysis" The model consisted of selecting tools, collecting and analyzing data, finding problems and exploring problems. The teaching strategy is composed of seven principles necessary for each stage of the model, and is divided into instructional strategies and guidelines for environment composition. The development of the ESDA inquiry model and teaching strategy is not easy to generalize to the whole school level because the sample was not large, and research was qualitative. While this study has a limitation that a quantitative study over large number of students could not be carried out, it has significance that practical model and strategy was developed by approaching the knowledge-information-processing competency with respect of science inquiry.

• Journal of Nutrition and Health
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• v.47 no.6
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• pp.443-451
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• 2014

Purpose: This study was conducted for analysis of menu pattern and food diversity of snack menus of child care centers in order to provide preliminary data for establishment of related guidelines for snack menus for child care centers. Methods: Data from 630 snack menus (350 for morning snacks and 280 for afternoon snacks) of March, 2013 from 14 Child Care Information Centers in Seoul provided for child care centers were analyzed. In addition, the menu pattern and food diversity of morning snack menus were compared with those of afternoon snack menus. Results: Differences in menu pattern and food diversity were observed between morning and afternoon snack menus. The majority of snack menus (66.8%) included two menu items and the numbers of menu items of afternoon snack menus were significantly larger than those of morning snack menus. The percentages of "Grains (G)" and "Grains (G) + Milk (D)" patterns were higher in snack menu (G: 18.9%, G+D: 17.1%). Approximately one third of snack menus were composed of only one food group. In addition, 45.6 % of all snack menus comprised milk and only 23.0% included fruits. Conclusion: These results demonstrated the need for improvement in food composition and diversity of snack menus provided by Child Care Information Centers for child care centers. Therefore, to ensure children's intake of nutritionally balanced snacks, it will be necessary to establish more detailed guidelines for the menu pattern and food composition in snack menus for child care centers.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.423-433
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• 2017

Korea Institute of Geoscience and Mineral Resources and Department of Geological Survey and Mineral Exploration in Myanmar have explored the Kalaymyo chromitite deposit, Myanmar since 2013. It is now necessary to find a geochemical indicator for efficient mineral exploration in the future and building a 3D geological model for this ore deposit. Mantle podiform chromitite is a major type of Cr ore in this region, which is considered to be formed by mantle-melt interaction beneath the mantle-crust boundary of oceanic lithosphere. In this study we measured major element composition of spinels in harzburgite, dunite and chromitite, and examined the hypothesis that spinel Cr#(molar Cr/(Cr+Al)${\times}$100) can be used as a geochemical indicator in exploration for the Kalaymyo chromitite. The results show that there is a clear correlation between spinel Cr# and distribution of chromitite. The spinel Cr# of harzburgite increases with decreasing the distance from the chromitite bodies. The spinel composition is also closely associated with texture and occurrence of spinels. The high Cr# spinels (30-48) are subhedral to euhedral and enclosed by olivine whereas the low Cr# spinels (16-27) are anhedral and commonly associated with pyroxenes. Often the low Cr# spinels show symplectite intergrowths with pyroxenes, indicating their residual nature. These petrological and geochemical results suggest that the high Cr# spinels have resulted from mantle-melt interaction. We suggest that spinel Cr# can be used as a geochemical indicator for Cr ore exploration and as one of critical factors in 3D geological model in the Kalaymyo chromitite deposit.

• 한국노년학
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• v.36 no.3
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• pp.525-540
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• 2016

The purpose of this study was to investigate what kind of experiences the deaf elderly would have in the course of life. It also aimed to promote the understanding of their living difficulties and culture among people with normal hearing and provide basic data to help them live with others as members of the community. Phenomenological qualitative research was conducted as part of the methodology. The subjects include seven deaf old people. Based on the results of in-depth interview and analysis, the life experiences of the deaf elderly were categorized into "unforgettable wounds," "life in the community," "life with the family," "marriage of the deaf elderly", and "living by adjusting to reality." First, the subcategories of "unforgettable wounds" include "receiving no treatment for fever," "damage by the Korean War," "alienation from the family," and "people's cold eyes." It turned out that the deaf elderly had led a life, suffering from the heart wounds that they could not forget. Second, the subcategories of "life in the community" include "inconvenience in life," "disadvantages in life," and "severed life." The deaf elderly were not only subjected to inconvenience and disadvantages in life, but also suffered loneliness, being cut off from the community. Third, the subcategories of "life with the family" include "not communicating with children," "being abandoned again," "being used by the family," "being lonely even with the family," and "wishing to live independently from the family." The deaf elderly were not supported by their families and were abandoned or used by them, leading a solitary life. Fourth, the subcategories of "marriage of the deaf elderly" include"send as a surrogate mother," "frequent remarriage and divorce," "lean on as a married couple." Deaf elderly form their own culture of the marriage and lean on each other. Finally, the subcategories of "living by adjusting to reality" include "getting help from neighbors," "behaving oneself right in life," "learning Hangul," "living by working," "living freely," "living by missing," and "controlling the impulse to end life," "resorting to religion." The deaf elderly made the most alienated and vulnerable group with no access to benefits due to their limitations as a linguistic and social minority, but they made efforts to form their own culture and adjust to reality for themselves. Based on those findings, the study made the following proposals: first, there is a need for practical approaches to heal the ineffaceable wounds in the hearts of deaf elderly. Second, there is a need for policies to help them experience no inconvenience and disadvantages as members of community and communicate with people with normal hearing. Third, there should be practical approaches to enable them to get recognition and support from their families and share love with them. Finally, there should be practical policy approaches to help people with normal hearing understand the culture of deaf elderly and assist the deaf elderly to receive supports from the community and live with others within the community.

• Korean Journal of Environment and Ecology
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• v.27 no.2
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• pp.241-252
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• 2013

This study investigated plant community structure of Dongbaekdongsan(Mt.) in Jeju-do to identify character as evergreen broad-leaved forest. 20 plots(size is $20m{\times}20m$) were set up and plant communities were divided into 5 communities of Quercus glauca-Castanopsis cuspidata var. sievoldii-Ilex integra(Camellia japonica), Quercus glauca-Castanopsis cuspidata var. sievoldii-Camellia japonica, Quercus glauca-Camellia japonica, Quercus glauca-Camellia japonica-Pinus thunbergii and Pinus thunbergii-Quercus glauca by using TWINSPAN, DCA ordination, mean importance value and environmental condition. Area of Evergreen broad-leaved forest with stonny ground is covered with Quercus glauca and Castanopsis cuspidata var. sievoldii in canopy layer and Camellia japonica in the subordinate layer. Area of remaining soil's depth is covered with Pinus thunbergii. It has been alleged that Pinus thunbergii planted by human when Dongbaekdongsan(Mt.) is not selected local monuments. All of communities is predicted success to community of Quercus glauca-Camellia japonica. Shannon's diversity ranged from 1.0268 to 1.0717 in area of Evergreen broad-leaved forest and 1.2102 in area of Pinus thunbergii. 10 species of broad-leaved tree's constancy ratio is over the 80%. In future, Castanopsis cuspidata var. sievoldii and Cinnamomum japonicum can cover canopy layer, but it has low importance value. Specially high aged Camellia japonica is appeared everywhere. It has been alleged that it was touched by divinity since past. Dongbaekdongsan(Mt.) has different plant structure with another evergreen broad-leaved forest. It is hard that knowing its successional sere because it was damaged when it isn't degignate local monument. Accordingly continuous monitoring was required, successional direction and community's character is identified after forest become steady.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.1
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• pp.26-46
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• 2020

An irrigated-maize agroecosystem is viewed as an open thermodynamic system upon which solar radiation impresses a large gradient that moves the system away from equilibrium. Following the imperative of the second law of thermodynamics, such agroecosystem resists and reduces the externally applied gradient by using all means of this nature-human coupled system acting together as a nonequilibrium dissipative process. The ultimate purpose of our study is to test this hypothesis by examining the energetics of agroecosystem growth and development. As a first step toward this test, we employed the eddy covariance flux data from 2003 to 2014 at the AmeriFlux NE1 irrigated-maize site at Mead, Nebraska, USA, and analyzed the energetics of this agroecosystem by scrutinizing its radiation, energy and entropy exchange. Our results showed: (1) more energy capture during growing season than non-growing season, and increasing energy capture through growing season until senescence; (2) more energy flow activity within and through the system, providing greater potential for degradation; (3) higher efficiency in terms of carbon uptake and water use through growing season until senescence; and (4) the resulting energy degradation occurred at the expense of increasing net entropy accumulation within the system as well as net entropy transfer out to the surrounding environment. Under the drought conditions in 2012, the increased entropy production within the system was accompanied by the enhanced entropy transfer out of the system, resulting in insignificant net entropy change. Drought mitigation with more frequent irrigation shifted the main route of entropy transfer from sensible to latent heat fluxes, yielding the production and carbon uptake exceeding the 12-year mean values at the cost of less efficient use of water and light.