• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.24-34
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• 1992

Recent studies dealing with the fundamental understanding and applications of bimetallic catalysts are discussed. Bimetallic catalysts have had a major industrial impact, specifically for the reforming of petroleum naphtha, for the hydrogen reduction of carbon monoxide, and for the three way catalytic converter system. The action of the bimetallic catalysts in these reactions may be interpreted in terms of ensembles, electronic influences and surface structure. Various combinations of metal pairs have been considered in order to evaluate the role played by the added metals. For catalyst selectivity control, the possibility of surface enrichment of one element has been recognised. More generally, the influence of preparative variables on the formation of supported catalysts has been clarified, In particular by temperature programmed reduction (TPR). Information on the structure of bimetallic catalysts has been obtained with chemical probes, such as chemisorption and reaction rate measurement and physical probes, such as extended X-ray absorption fine structure (EXAFS), scanning transmission electron microscopy (STEM) and Xe-NMR.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.265-270
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• 2017

PURPOSE. This study is to evaluate the internal fit of the crown manufactured by CAD/CAM milling method and 3D printing method. MATERIALS AND METHODS. The master model was fabricated with stainless steel by using CNC machine and the work model was created from the vinyl-polysiloxane impression. After scanning the working model, the design software is used to design the crown. The saved STL file is used on the CAD/CAM milling method and two types of 3D printing method to produce 10 interim crowns per group. Internal discrepancy measurement uses the silicon replica method and the measured data are analyzed with One-way ANOVA to verify the statistic significance. RESULTS. The discrepancy means (standard deviation) of the 3 groups are $171.6\;(97.4){\mu}m$ for the crown manufactured by the milling system and 149.1 (65.9) and $91.1\;(36.4){\mu}m$, respectively, for the crowns manufactured with the two types of 3D printing system. There was a statistically significant difference and the 3D printing system group showed more outstanding value than the milling system group. CONCLUSION. The marginal and internal fit of the interim restoration has more outstanding 3D printing method than the CAD/CAM milling method. Therefore, the 3D printing method is considered as applicable for not only the interim restoration production, but also in the dental prosthesis production with a higher level of completion.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.100-113
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• 2016

Purpose: This study was performed to investigate the influence of children's hospital nurses' job characteristics and job stress on turnover intention. Method: The subjects were 148 nurses who have been working in 6 children's hospitals located in G city. Measurement tools used for this study included job characteristics were created by Lee, and modified by Hong, and job stress tool developed Kim & Ku and modified by Choi. And the tools used for assessing turnover intention were created by Mobley and Becker and modified by Kim. The collected data was analyzed using descriptive statistics, the independent t-test, one-way ANOVA, Pearson' Correlation and regression on SPSS 21.0 program. Result: Job challenge and job fitness among the sub-areas of job characteristics, job stress and salary were identified as factors influencing turnover intention. These factors explained 36.5% of variance of turnover intention. Conclusion: In conclusion, this results can be used to help the children's hospitals creates an environment where nurses can enhance Job challenge and job fitness also, reduce job stress which lead to turnover rate and turnover intention.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.289-300
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• 2016

This research purposed to verify early childhood teacher's self-differentiation and self-efficacy on psychological well-being. The subjects were 293 teachers in 39 early childhood education institutions in K city and J province.The research tools for measurement have been used to self-differentiation (Je Seokbong, 1989) self-efficacy(Park Seonyeong, 2012) and psychological well-being(Ko Kyungae, 2010). The data is analyzed through t test, one-way analysis of variance, correlation, regression analysis. In conclusion, their ages of general background that have a distinction betweeen self-differentiation and self- efficacy as well as psychological well-being, these two self-defferenciation and self- efficacy have a correlation and for being affected by psychological well-being as a fluctuation. That is, teachers who have psychological struggle and anxiety are insufficient to teach young children warmly and comfortably, therefore, they should accept self and young children positively, maintain warm relationship, and develop their own ability or talent, and achieve self matureness as professionals.

• Speech Sciences
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• v.9 no.4
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• pp.93-103
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• 2002

The purpose of this study was to establish preliminary data on the speech rates in groups of normal speaking adults and children. The results of the present study are intended to serve as clinical measurement guidelines for diagnosis, assessment, treatment planning, and therapy progresses of stuttering. Thirty-one adults (16 females, 15 males), aged 18-30 years and thirty normally developing children (15 females, 15 males), aged 8-10, participated in the study. The subjects' reading of the Stroll (Jeong, 1994) passage and l-minute portion of talking about the daily routine were sampled. The adult speakers had rates of $308.29\pm22.57$ syllables per minute (SPM) or $108.06\pm6.17$ words per minute (WPM) during reading, and $252.87\pm40.86$ SPM and $92.26\pm17.12$ WPM during talking. The children had rates of $176.67\pm33.65$ SPM or $64.07\pm12.62$ WPM during reading, and $149.30\pm33.14$ SPM and $56.60\pm11.36$ WPM during talking. The results of t-tests for reading and talking tasks in adults showed that SPM in reading (t=2.211, p< .05) and WPM in talking (t=-2.284, p< .05) differed significantly by the gender. To answer the questions whether the rate is different across children' s gender and age, a two-way ANOVA was performed. Both SPM and WPM in reading tasks were significantly different between groups of children aged 8 and 10 (p< 01), In speaking tasks, both SPM and WPM were significantly different between groups of children aged 8 and 10, and between 9 and 10.

• Journal of Korean society of Dental Hygiene
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• v.18 no.5
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• pp.853-862
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• 2018

Objectives: This study involved a non-equivalent control group, pre-test/post-test measurement experiment to evaluate the efficacy of distributing plaque disclosing agents to healthy adults living in South Korea and promoting its self-application. Methods: O'Leary index, PHP index, oral health behavior intention, and oral care satisfaction were used as research tools. A notice was posted on the bulletin board from September 12 to October 15, 2016, to recruit adults aged 20-50 years. Data were analyzed using SPSS Version 22.0, and frequency analysis, Pearson's chi-squared, one-way analysis of variance (ANOVA), Kruskal-Wallis, and repeated measures ANOVA were performed. Results: The O'Leary index was significantly reduced in the group (p<0.01), and time (p<0.01) after education and width of the decrease had the highest score in the group that received education on plaque disclosing only. They were followed by the group that received education on plaque disclosing and the rolling method, the group that received education on the rolling method alone, and the control group. The PHP index significantly decreased in the group(p<0.01) and time (p<0.01), and the group time (p=0.039) after education, and width of the decrease had the highest score in the group that received education on plaque disclosing and rolling method. They were followed by the group that received education on plaque disclosing alone, the group that received education on the rolling method alone, and the control group. Conclusions: Based on the aforementioned findings, the direct use of plaque disclosing had a marked effect on self-oral care. These results suggest that the self-application of plaque disclosing could be an effective self-care method for improving the oral environment.

• Journal of Biosystems Engineering
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• v.40 no.1
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• pp.19-27
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• 2015

Purpose: A system to measure the visibility of agricultural tractor operators was designed and evaluated according to ISO standards, and a blind area diagram around the tested tractor was created based on the manual method recommended by the National Institute for Occupational Safety and Health (NIOSH). Methods: A visibility measurement system was designed and evaluated based on the ISO 5006 and ISO 5721-1 standards. Two bulbs used to simulate the operator's eyes were mounted on a bar with a supporting frame. A wooden frame was used to determine the seat index point position. The 12-m visibility test circle was divided into six sectors of vision, and the test tractor was placed at the center of the circle. Artificial light was supplied in the darkened environment, and shadow or masking effects were measured manually around the 12-m circle. Results: When the bulbs were placed at the operator's eye level, front visibility was good; no masking was found in the "A" vision sector, but larger masking widths were found in the "B" and "C" vision sectors. Since the masking width exceeded 700 mm, additional tests, such as movement of the light sources to both sides of the operator's eye level, were performed. Less than six masking effects were found in the semi-circle of vision to the front, and more than one masking was found in the "B" and "C" visual fields. The minimum distance between the centers of two masking effects exceeded 2500 mm when measured as a chord on the semi-circle of vision. A blind area diagram was created to define the exact nature of the blind spots and mirror visibility. Conclusions: Visibility evaluation is an effective way to enable proper and safe operation for agricultural tractor operators. Inclusion of this visibility evaluation test in the general testing process might aid tractor manufacturers.

• The Korean Journal of Pain
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• v.12 no.1
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• pp.87-94
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• 1999

Backgroud: We have performed the CT-guided celiac plexus block (CPB) using anterior approach to evaluate the safety and efficacy of the procedure and to determine the role of CT. Methods: CPB were done in 10 patients (5 men and 5 women: mean age, 58.1 years) with intractable upper abdominal pain due to terminal malignancy of the stomach (n=3), pancreas (n=4), gallbladder (n=2), and liver (n=1). To permit an anterior approach, patients lay supine on the CT scan table during the procedure. One 21-guage Chiba needle was placed just anterior to the diaphragmatic crus between the celiac and superior mesenteric arteries and 10~12 ml of dehydrated alcohol was injected. Degree of pain relief following the procedure was assessed and pain was graded on a numeric rating scale (NRS) from 0 to 10. Results: The results suggest a direct relation between the degree of celiac invasion and the response to the CPB. With CT guidance, it is possible for us to direct the needle into more accurate region, allowing alcohol to be deposited in specific ganglion area. Conclusions: CT-guided CPB using an anterior approach was an easy and effective way of reducing intractable upper abdominal pain due to terminal malignancies. CT-guidance allowed precise needle placement and safe procedure. Careful classification of cases is important to predict the degree of pain relief using the grading system based on the degree of involvement of the celiac plexus.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.687-693
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• 2016

Objectives: The purpose of the study was to investigate the influence of instructor trust on learning flow and academic achievement in dental hygiene students. Methods: A self-reported questionnaire was completed by 202 dental hygiene students in Gyeongnam from July to August, 2016. A five point Likert scale questionnaire consisted of intimacy (8 items), professionalism (8 items), teaching ability (5 items), and leadership (6 items). Measurement of learning flow was adapted and modified by Kim et al. Academic achievement was adapted and modified by Noe and Schmitt. Cronbach's ${\alpha}$ of learning flow was 0.77 and that of academic achievement was 0.78 in the study. Data wee analyzed by t-test, one way ANOVA, $Scheff{\acute{e}}$ test, and Pearson's correlation using SPSS 23.0 program. Results: The scores of instructor trust, learning flow, and academic achievement were 4.37, 3.46, and 3.23, respectively. Academic achievement had a close positive correlation with instructor trust (r=0.46, p<0.001) and learning flow (r=0.63, p<0.001). Instructor trust had a positive correlation with learning flow (r=0.50, p<0.001). Learning flow took mediating effects on instructor trust and academic achievement. Conclusions: The trust between students and instructors had a great influence on learning flow and academic achievement. So the instructor should try to make the students concentrate on learning.

• Journal of Elementary Mathematics Education in Korea
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• v.9 no.2
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• pp.161-180
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• 2005

The purpose of this study is to delve into how elementary mathematics textbooks deal with the areas of triangles and quadrilaterals from a viewpoint of the Didactic Transposition Theory. The following conclusion was derived about the teaching of the area concept: The area concept started to be taught perfectly in the 7th curricular textbook, and the focus of area teaching was placed on the area concept, since learners were gradually given opportunities to compare and measure areas. As to the area formulae of triangles and quadrilaterals, the following conclusions were made: First, the 1st curricular, the 2nd curricular and the 3rd curricular textbooks placed emphasis on transposition by textbooks, and the 4th curricular, the 5th curricular and the 6th curricular textbooks accentuated transposition by teachers. The 7th curricular textbooks put stress on knowledge construction by learners; Second, the focus of teaching shifted from a measurement of area to inducing learners to make area formula. Namely, the utilization of area formula itself was accentuated, while algorithm was emphasized in the past; Third, the way to encourage learners to produce area formula changed according to the curricula and in light of learners' level, but a wide range of teaching devices related to the area formulae were removed, which resulted in offering less learning chances to students; Fourth, what to teach about the areas of triangles and quadrilaterals was gradually polished up, and the 7th curricular textbooks removed one of the overlapped area formula of triangle.