• Clean Technology
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• v.21 no.3
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• pp.153-163
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• 2015

The effects of H₂O and residue SO₂ in flue gases on the activity of the Fe/zeolite catalysts for low-temperature NH₃-SCR of NO were investigated. And the addition effect of Mn, Zr and Ce to Fe/zeolite for low-temperature NH₃-SCR of NO in the presence of H₂O and SO₂ was investigated. Fe/zeolite catalysts were prepared by liquid ion exchange and promoted Fe/zeolite catatysts were prepared by liquid ion exchange and doping of Mn, Zr and Ce by incipient wetness impregnation. Zeolite NH₄-BEA and NH₄-ZSM-5 were used to adapt the SCR technology for mobile diesel engines. The catalysts were characterized by BET, X-ray diffraction (XRD), SEM/EDS, TEM/EDS. The NO conversion at 200 ℃ over Fe/BEA decreased from 77% to 47% owing to the presence of 5% H₂O and 100 ppm SO₂ in the flue gas. The Mn promoted MnFe/BEA catalyst exhibited NO conversion higher than 53% at 200 ℃ and superior to that of Fe/BEA in the presence of H₂O and SO₂. The addition of Mn increased the Fe dispersion and prevented Fe aggregation. The promoting effect of Mn was higher than Zr and Ce. Fe/BEA catalyst exhibited good activity in comparison with Fe/ZSM-5 catalyst at low temperature below 250 ℃.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.2
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• pp.145-156
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• 2005

An artificial disturbance like forest fragmentation has affected the sustainability of forest ecosystem. Therefore, in order to manage the forest ecosystem efficiently needed to analyze quantity and quality (structural pattern) of forest simultaneously. This study analyzed the structural patterns of forest landscape to provide a basic data for evaluation and management of forest ecosystem in Nakdong River Basin during 10 years from 1980s to 1990s using landscape indices and GIS methods. Forest distribution maps and 6 landscape indices(LPI, PD, ED, MSI, CPLAND, IJI) for the analysis were reconstructed from land-cover maps constructed by Ministry of Environment and pearson correlation analysis. According to the structural analysis of forest landscape using landscape indices, the forest fragmentation of watersheds along the main stream of the Nakdong river was more severe than any other watersheds. Futhermore, the Nakong-sangju and Nakdong-miryang watersheds had unstable forest structures as well as least amount of forest quantity. Thus, these watersheds need significant amount of forest through a new forest management policy considering local environmental conditions. The connectivity between forests in local regions should be considered as well.

• Communications of Mathematical Education
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• v.25 no.1
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• pp.245-259
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• 2011

In this study, the instrument of mathematical creative problem solving ability test were considered the differences between Korean and American sixth grade students in mathematical creativity ability and mathematical thinking ability. The instrument consists of 9 items. The participants for the study were 212 Korean and 148 American students. SPSS were carried out to verify the validities and reliability. Reliabilities(Cronbach ${\alpha}$) in mathematical creativity ability is 0.9047 and in mathematical thinking ability is 0.9299 which were satisfied internal validity evaluation on the test items. Internal validity were analyzed by BIGSTEPS based on Rasch's 1-parameter item response model. The results of this study can serve as a foundation for understanding the Korean and American students differences in mathematical creativity ability and mathematical thinking ability. Especially we get the some informations on mathematical creativity ability for American's fifth grade to seventh grade students.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.48-54
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• 1997

This study was performed to develop the biological treatment technology of wastewater polluted with heavy metals. The copper-tolerant bacteria, Pseudomonas stutzeri which possessed the ability to accumulate copper, was isolated from mine wastewaters polluted with various heavy metals. The characteristics of copper accumulation in the cells and the recovery of the copper from the cells accumulating zinc, were investigated. Removal rate of copper from the solution containing 100mg/l of copper by copper-tolerant bacteria was more than 78% at 2 days after inoculation with the cells. A large number of the electron-dense granules were found mainly on the cell wall and cell membrane fractions, when determined by transmission electron microscopy. Energy dispersive X-ray spectroscopy revealed that the electron-dense granules were copper complex with the substances binding copper. The copper accumulated into the cells was not desorbed by deistilled water, but more than 80% of the copper accumulated was desorbed by 0.1M-EDTA solution. The residues of the cells after combustion at $550^{\circ}C$ amounted to about 23.2% of the dry weight of the cells. EDS analysis showed that residues were relatively pure copper compound containing more than 78.4% of copper.

• Journal of the Korean earth science society
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• v.25 no.4
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• pp.242-250
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• 2004

The purpose of this study is to examine the interactive effects of teaching methods (expository and discovery) and learner's cognitive styles on the retention of learned content in Earth Science three weeks after an instruction is given. The subjects of this study were 1st graders of a boys' high school (n = 185) and co-educational high school (n = 189) in Gwangiu Metropolitan City of Korea. 92 students of the boys' high school and 95 students of the co-ed high school were assigned to the expository teaching group, and the rest of the boys' high school students and the co-ed high school students were to the discovery teaching group. The students were classified into field-independent learners, medium learners, and field-dependent learners based on their cognitive styles. The results of the study can be summarized as follows: First, the discovery teaching was more effective than expository teaching in terms of comprehension and application related to post-instruction retention of learned content. But there was no noticeable difference in knowledge domain. Second, the field-independent cognitive style was more effective than its counterpart, the field dependent cognitive style. Third, in the post-instruction retention test, not so much relevance was found between teaching methods and learner's cognitive style.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.8 no.2
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• pp.127-133
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• 2012

Ehlers-Danlos syndrome (EDS), an inherited connective tissue disorder, is caused by mutations in genes encoding different types of collagen or collagen-processing enzymes. EDS most typically affects the joints, ligaments, skin, and blood vessels. Oral health may be severely compromised in EDS as a result of specific alterations of collagen in orofacial structures. Dental hard tissue defects, root dilaceration, pulp stones, ectopic or delayed eruption, impaction, and periodontal disease could be observed. Therefore, a number of tissue responses related to collagen and precautions should be anticipated when considering dental treatment in EDS. Long-term and comprehensive dental management is required. The purpose of this report is to describe a clinical case of eruption disorders in a patient with EDS.

• The Korean Journal of Pain
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• v.26 no.2
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• pp.148-153
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• 2013

Background: C-arm fluoroscope has been widely used to promote more effective pain management; however, unwanted radiation exposure for operators is inevitable. We prospectively investigated the differences in radiation exposure related to collimation in Medial Branch Block (MBB). Methods: This study was a randomized controlled trial of 62 MBBs at L3, 4 and 5. After the patient was laid in the prone position on the operating table, MBB was conducted and only AP projections of the fluoroscope were used. Based on a concealed random number table, MBB was performed with (collimation group) and without (control group) collimation. The data on the patient's age, height, gender, laterality (right/left), radiation absorbed dose (RAD), exposure time, distance from the center of the field to the operator, and effective dose (ED) at the side of the table and at the operator's chest were collected. The brightness of the fluoroscopic image was evaluated with histogram in Photoshop. Results: There were no significant differences in age, height, weight, male to female ratio, laterality, time, distance and brightness of fluoroscopic image. The area of the fluoroscopic image with collimation was 67% of the conventional image. The RAD ($29.9{\pm}13.0$, P = 0.001) and the ED at the left chest of the operators ($0.53{\pm}0.71$, P = 0.042) and beside the table ($5.69{\pm}4.6$, P = 0.025) in collimation group were lower than that of the control group ($44.6{\pm}19.0$, $0.97{\pm}0.92$, and $9.53{\pm}8.16$), resepectively. Conclusions: Collimation reduced radiation exposure and maintained the image quality. Therefore, the proper use of collimation will be beneficial to both patients and operators.

• Polymer(Korea)
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• v.38 no.2
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• pp.156-163
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• 2014

Hydroxyapatite has osteoconductivity, biocompatibility and noninflammatory, and it has been used clinically as artificial bone. In this study, we prepared hydroxyapatite/poly(lactic-co-glycolic acid) (PLGA) scaffolds using 0, 10, 20, 40 and 60 wt% of hydroxyapatite. We analyzed compressive strength, SEM analysis and FTIR for mechanical property of 3D hydroxyapatite/PLGA scaffolds. For biocompatibility tests, cell proliferation and viability were measured via MTT assay and SEM. We analyzed RT-PCR, FACS, histology (H&E, ED-1) for anti-inflammatory effect. This study showed that hydroxyapatite hybrid scaffolds have low inflammatory reaction compared with the PLGA. This result has a potential for the application of artificial bone graft material.

• Cross-Cultural Studies
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• v.24
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• pp.46-61
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• 2011

This paper considers how Koreans found their positions in the complex, overlapping, disjunctive, and interconnected "Oriental" repertoires in the early Cold War years. When we use the term, Oriental, it should require careful translation from context to context because it may be subject to very different sets of contextual circumstances. Klein views Cold War Orientalism in the complex of various regions including East Asian and Southeast Asian countries; however, when Koreans are contextualized at the center of the discussion the Orientalism produces another discursive meaning. Even though many great researches have been done on Korean immigrations, Korean American literatures, and US-Korea economic, political, and foreign relations, not many discussions about Korean American popular cultures have been discussed in the basis of the Oriental discourse in the United States.For this argument, this paper investigates the performative trajectory of a girl group "Kim Sisters" who began to sing at the US military show stages in South Korea in 1952 during the Korean War. They moved to Las Vegas show stages in 1959 and later appeared in Ed Sullivan Show more than thirty times during the 1960s and 70s. Meanwhile, they not only returned to South Korea often times to perform at the stages for Korean audiences in South Korea but also played at the shows for Korean immigrants in the United States. Korean American immigration to the United States has followed a different route from the majority of Asian American population such as Chinese or Japanese Americans, which means that efforts to compare this particular group to the others may be unnecessary. Rather doing comparative studies, this paper, therefore, focuses on the formation of the intersecting and multiple identities of Korean female entertainers who were forced or forced themselves to be incorporated into the American popular "Oriental" imagination, which I would call "embedded" identities. This embeddedness has been continuously maintained in the configuration of Korean characters in the United States. This will help not only to observe the discursive aspect of Asian American identity politics but also to claim a space for comparatively invisible Korean characters in the United States which has been often times neglected and not brought into a major Asian American or Oriental historical discourse. This paper starts with American scenes at the beginning of the twentieth century to trace Americans Oriental imagination which was observable in the various American cultural landscape and popular music soundscape. It will help us more clearly understand the production and consumption of the Korean "Oriental" performances during the early Cold War period and especially the Korean performance in the American venue, silently overshadowed into the political, social, and cultural framework.

• Journal of Industrial Convergence
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• v.20 no.8
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• pp.77-84
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• 2022

This study aims to present a method for implementing a decision support system that can be used for selecting emerging technologies by applying a machine learning-based automatic classification technique. To conduct the research, the architecture of the entire system was built and detailed research steps were conducted. First, emerging technology candidate items were selected and trend data was automatically generated using a big data system. After defining the conceptual model and pattern classification structure of technological development, an efficient machine learning method was presented through an automatic classification experiment. Finally, the analysis results of the system were interpreted and methods for utilization were derived. In a DTW-kNN-based classification experiment that combines the Dynamic Time Warping(DTW) method and the k-Nearest Neighbors(kNN) classification model proposed in this study, the identification performance was up to 87.7%, and particularly in the 'eventual' section where the trend highly fluctuates, the maximum performance difference was 39.4% points compared to the Euclidean Distance(ED) algorithm. In addition, through the analysis results presented by the system, it was confirmed that this decision support system can be effectively utilized in the process of automatically classifying and filtering by type with a large amount of trend data.