• Elastomers and Composites
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• v.33 no.3
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• pp.201-209
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• 1998

Alumina powders used as a filler in rubber compounding was extracted from kaolin in $H_2SO_4$ solution employing conventional thermal and microwave energy resources. Maximum degrees of alumina extraction from kaolin were 72.8% at $80^{\circ}C$, 1M $H_2SO_4$, and 180min in the conventional thermal extraction process and were 99.0% at $90^{\circ}C$, 1M $H_2SO_4$,, and 60min in the microwave extraction one, respectively. The samples synthesized in both processes were analyzed by means of TG/DTA, XRD, SEM, Atomic Emission Spectroscopy, and BET method. Studies are presently under way to unravel the basic interaction mechanisms between microwave and alumina power for high rates of alumina extraction from kaolin in the microwave ex-traction process.

• Journal of Information Technology Applications and Management
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• v.14 no.3
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• pp.179-197
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• 2007

This paper analyzed the effects of interactions among participants on the satisfaction and commitment of cyber education. Even if the quality of interactions in cyber education may not be so good as that of interactions in face to face education. various kinds of interactions could be introduced in cyber education. An email or Q/A between lecturer and students could be a good way to compensate the deficiency of cyber education. Common News Boards or Discussion Rooms among students themselves are also a powerful means to learn each other in cyber space. The result of this study shows that as interactions among participants increase. satisfaction and commitment of the lecture also increase. This study also analyzed how cyber educational effects differs as interaction type changes in space dimension and time dimension. The result shows interactions in the same cyber space such as News Board brings more desirable outcome than those in the different cyber space. But the effects of interactions classified by time dimension does not show statistically significant differences.

• 모자간호학회지
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• v.4 no.1
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• pp.52-67
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• 1994

This study was done to investigate mother's attitude to breast feeding and the type of feeding according to the general characteristics of mother. The study sample consisted of 1696 mothers who had an infant and who were visiting five Hospitals or ten Public Health Centers in Seoul. Data was collected through a question aire from June, 1 to June, 30, 1993. The results are as follows : 1. The types of feeding were artificial feeding 2%), mixed feeding(21.7%) and breast feeding (26.1%). 2. The attitude of mothers to breast feeding was very positive for behavior tendency and cognitive attitude but the emotional attitude was low to moderate. 3. The attitude scores for the mothers were from 27 to 60 and 65% the mothers had scores that were high, 50-60 and mean was 49.86. 4. There was the significance between the general characteristics (type of delivery, obtaining in formation on breast feeding, type of feeding and baby's birth order) and the attitude score of mothers. 5. The attitude scores for the mothers by the general characteristics and type of feeding was not a 2-way interaction but the type of feeding had a main effects.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.109-118
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• 2010

Using a speeded classification task (Garner, 1978), we investigated the perceptual interaction of distinctive features in Korean consonants. The main questions of this study were whether listeners can perceptually identify the component features that make up complex consonant sounds, whether these features are processed independently or dependently and whether there is a systematic hierarchy in their dependency. Participants were asked to classify syllables based on their difference in distinctive features in the task. Reaction times for this task were also gathered. For example, participants classified spoken syllables /ta/ and /pa/ as one category and /$t^ha$/ and /$p^ha$/ as another in terms of aspiration condition. In terms of articulation, participants classified /ta/ and /$t^ha$/ as one category and /pa/ and /$p^ha$/ as another. We assumed that the difference between their RTs represents their interdependency. We compared the laryngeal features and place features (Experiment 1), resonance features and place features (Experiment 2), and manner features and laryngeal features (Experiment 3). The results showed that distinctive features were not perceived in a completely independent way, but they had an asymmetric and hierarchical interdependency. The laryngeal features were found to be more independent compared to place and manner features. We discuss these results in the context of perceptual basis in phonology.

• YAKHAK HOEJI
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• v.54 no.1
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• pp.13-21
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• 2010

The interaction of cadmium (II) ion with quercetin, qurecitrin and (+)-catechin was investigated in aqueous solution at various pH. The flavonoid/cadmium stochiometries for cadmium (II) binding to flavonoid have been determined by UV-visible spectroscopy. 1:1 Cd(II)-Flavonoid complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH, that occurs upon complexation, is due to a ligand-tometal charge transfer. The optimal concentration of Cd(II)-flavonoid complexes showed that complexation reaction could be classified in the following way: 55.27 ${\mu}M$ catechin > 54.72 ${\mu}M$ quercetin > 53.52 ${\mu}M$ quercitrin at the chelating site level. These results suggest that Cd(II)-flavonoid complex has the optimal condition of chelation in 0.2 M $NH_3$ - 0.2 M $NH_4Cl$ (pH 8.0) solution.

• The Mathematical Education
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• v.49 no.3
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• pp.353-373
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• 2010

This research was to help slow learners to be motivated and to make their outcome productive, using GSP based on the mathematization theory for learning mathematics, as a way of encouraging the learner-centered approach. With 2 of the second graders in a high school, who had not yet understood trigonometric functions in their first grade period, 7 units of lesson plans were designed for the research. The results showed that first, understanding real life contexts and analyzing properties by observation, and experiment using GSP, to build the concept of trigonometric functions could be a foothold on which learner's organization and outcome from a horizontal mathematization led to vertical mathematization. Despite the delay during the level-up-stage for a while, the learners could attain the vertical mathematization stage and moreover the applicative mathematization through effective use of GSP and the interaction between the learners or a teacher and the learners. Second, using GSP was a vertical tool of connecting horizontal mathematization with vertical mathematization in forming the concept of trigonometric functions and its meaning could be understood by their verbalizing and presenting the outcomes through their active performance. Using GSP is helpful for slow learners to overcome learning difficulties, based on the instructional materials designed by Realistic Mathematics Education.

• Journal of Engineering Education Research
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• v.13 no.4
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• pp.122-129
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• 2010

This study was conducted to compare the self-leadership strategies and locus of control between the problem-solving styles in the Korean engineering college students. Creative problem-solving styles were identified based on the three dimensions. The results of the two-way analysis of variances indicated the main effects of problem-solving styles; each problem-solving style had unique characteristics in relation to self-leadership strategies and locus of control. There were neither main effects of sex nor interaction effects of problem-solving styles and sex. It would be useful to provide the engineering students with the specialized self-leadership training program based on the problem-solving styles.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.1-16
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• 1995

This study was carried out to suggest method which can be used to improve competitive power of theme parks. The characteristics of Hybrid Conjoint Analysis were described and its usefulness for identification of specific types of service theme parks have to provide was tested "Lotte World, " "Seoul land," and "farmland" were selected as study areas, and .7 attributes with 3 levels were utilized for analyses. Master design with 81 profiles was constructed to meet the requirement of ′Compromise Plan 1,′and data was collected by in-personal interviews on the study areas. Respondents were grouped by cluster analysis, and their characteristics were analyzed by discriminant analysis. Then, part-worth of each attribute . was estimated by stagewise estimation model Calibrated model of each group did not show part-worths of attributes clearly because both main effects and 2-way interaction effects were included in the models. Therefore, calibrated models′ coefficients were used to calculate utilities of all possible combinations of attributes levels. The results showed that managers of theme parks have several options for providing a new service: the combination of attribute levels with the highest utility is they however, they can choose the other combinations with next highest utlities is they can not afford it. Several suggestions were described to cope with the problems when Hybrid Conjoint Analysis is applied to landscape architectural study.

• The Journal of Korean Academic Society of Nursing Education
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• v.28 no.1
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• pp.15-26
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• 2022

Purpose: The purposes of this study was to describe the lived experience structures of married immigrant women with chronic diseases in reorganizing their lives in a variety of situations and contexts. Methods: This study applied grounded theory approach, and the participants were 15 married immigrant women with chronic disease. Data were collected through individual in-depth interviews and then analyzed by the method in Strauss and Corbin (1998). Results: The extracted data were organized 41 concepts, 21 subcategories, and 8 categories. The central phenomenon was determined to be "Life turned into a chronic disease." The causal conditions were "Undergoing physical and mental stress from marriage", "Lack of information on chronic diseases." The extracted contexts was "The demand for health resources." action and interaction strategies, "Finding problems and solutions." The intervention conditions influencing the strategies was "Establishing a support system." The result of such action was "To settle down in a way of life that suits your conditions." Conclusion: By providing a comprehensive and integrative understanding of how married immigrant women with chronic disease reorganize their lives, the study is expected to contribute to the development of social systems and national policies.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.873-879
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• 2024

A sodium-cooled fast reactor (SFR) core has a potential of prompt criticality due to a change of core material distribution during a severe accident, and the resultant energy release has been one of the safety issues of SFRs. In this study, the safety assessment of an unprotected loss-of-flow (ULOF) in a small SFR (SSFR) has been performed using the SIMMER-IV computer code, which couples the models of space- and time-dependent neutronics and multi-component, multi-field thermal hydraulics in three dimensions. The code, therefore, is applicable to the simulations of transient behaviors of extended disrupted core material motion and its reactivity effects during the transition phase (TP) of ULOF, including a potential of prompt-criticality power excursions driven by fuel compaction. Several conservative assumptions are used in the TP analysis by SIMMER-IV. It was found out that one of the important mechanisms that drives the reactivity-inserting fuel motion was sodium vapor pressure resulted from a fuel-coolant interaction (FCI), which itself was non-energetic local phenomenon. The uncertainties relating to FCI is also evaluated in much conservative way in the sensitivity analysis. From this study, the ULOF characteristics in an SSFR have been understood. Occurrence of recriticality events under conservative assumptions are plausible, but their energy releases are limited.