• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1886-1896
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• 2019

Modern small modular nuclear reactors can be built on a barge in ocean, therefore, their flow characteristics depend upon the ocean motions. In the present research, effect of rolling motion on flow and friction characteristics of laminar flow through vertical and horizontal narrow channels has been studied. A computer code has been developed using MPS method for two-dimensional Navier-Stokes equations with rolling motion force incorporated. Numerical results have been validated with the literature and have been found in good agreement. It has been found that the impact of rolling motions on flow characteristics weakens with increase in flow rate and fluid viscosity. For vertical narrow channels, the time averaged friction coefficient for vertical channels differed from steady friction coefficient. Furthermore, increasing the horizontal distance from rolling pivot enhanced the flow fluctuations but these stayed relatively unaffected by change in vertical distance of channel from the rolling axis. For horizontal narrow channels, the flow fluctuations were found to be sinusoidal in nature and their magnitude was found to be dependent mainly upon gravity fluctuations caused by rolling.

• Journal of Korean Elementary Science Education
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• v.39 no.3
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• pp.353-368
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• 2020

This study analyzed the teacher's perception for influence of behavioral characteristics of scientifically-gifted students on general students in elementary school science class. To do this, we selected the eight elementary school teachers who were conducting the regular science classes including scientifically-gifted students belonging to the gifted education institutes in Seoul and conducted individual in-depth interviews. The analysis of the results reveal that the teachers mentioned seven behavioral characteristics of scientifically-gifted students in general elementary school science classes.: 'excellent in designing and performing experiments', 'playing a leading role in experiments', 'expressing their abundant prior knowledge frequently', 'attempting their tasks with curiosity and persistence', 'displaying scientific creativity', 'often asking scientific questions in detail', and 'expressing their opinions logically'. These behavioral characteristics of scientifically-gifted students had positive effects on general students, such as 'providing them with a successful experience in conducting experiments', 'improving understanding of science class contents', 'developing scientific thinking and reflective thinking', and 'improving their students' positive experiences about science'. However, the excessive learning-driven behaviors of scientifically-gifted students had negative effects on general students, such as 'limiting opportunities for general students to participate in classes', 'conducting passive exploration centered on results', and 'causing conflicts with general students'. Educational implications of these findings are discussed.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.257-262
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• 2007

In this paper the experiments of breakdown characteristics by temperature change of $SF_6$ gas($GSF_6$), and $SF_6$ liquid ($LSF_6$) in model GIS (Gas Insulated Switchgear) are described. From the experiment's results, the breakdown characteristics classify the vapor stage of $SF_6$ according to Paschen's law, in which the gas & liquid coexisted stage of voltage value increases, resulting in much deviation and the breakdown of voltage ($V_B$) low stage as the interior of the chamber gets filled with a mixture of $SF_6$ that is not liquefacted and remaining air that cannot be ventilated. The ability of $LSF_6$ insulation is higher than the high-pressurized $SF_6$ gas. The breakdown characteristics of $LSF_6$ were produced by bubble formed evaporation of $LSF_6$ and bubbles caused by high electric emission. It is considered in this paper that the results are fundamental data for electric insulation design of superconductor and cryogenic equipments machinery that will be studied and developed in the future.

• The Journal of Korean Society for School & Community Health Education
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• v.15 no.1
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• pp.15-29
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• 2014

Objectives: The purpose of this study was to provide fundamental resources for preventing adolescents' bullying behavior. For this aim we analyzed parents' rearing attitudes and adolescents' personality characteristics effecting on bullying experiences. Methods: We carried out a questionnaire survey at middle and high school located in Anyang, Gwacheon, Gunpo from July 8 to 22, 2013. Data were collected from 756 students. By using SPSS 20.0, data were analyzed by descriptive statistics, correlation analysis, and hierarchical regression analysis Results: There was a close relationship among parents' rearing attitudes, adolescents' personality characteristics, and bullying experiences. Parents' affectionate rearing attitudes reduced adolescents' bullying experiences, on the other hand parents' hostile and rejective rearing attitudes increased. The adolescents with high responsibility had low bullying experiences, otherwise adolescents with high activity had high bullying experiences. Conclusions: In order to reduce bullying experiences parents' rearing attitudes should be changed and education programs that could encourage a sense of responsibility should be introduced.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1175-1184
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• 2022

The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (D_S) and the pore volume fractal dimension (D_V). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample's pore structure and the dissolution rate during the leaching was fitted.

• Journal of the Korean Home Economics Association
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• v.39 no.6
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• pp.93-108
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• 2001

After-school activities of 817 7th grade children from Kwangju, Busan, and Kumi were studied to determine relations with (a) child, family and contextual variables (b) child's academic achievement and social development. Children were more likely to engage in extracurriculum activites and TV watching than other after-school activities. After-school activities were related to child's, parent's and contextual variables. Child's characteristics related to after-school activities were sex, impulse control, mastery and self-care. family's characteristics related to after-school activities were mother's employment, emotional support, control, monitoring and SES. Region and regional sagy were related to after-school activities. Some of after-school activities were related child's academic achievement and social development. Especially academic activites have a positive and powerful effects on child's academic achievement and social development.

• Journal of the Korean Society of School Health
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• v.16 no.2
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• pp.125-134
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• 2003

Purposes of this study were 1) to identify the level of role expectation and role performance for school health educators as elementary school students recognize and to compare them, and 2) to examine differences in the role expectation and performance by characteristics of students and educators. Subjects of the study were 1,433 6th grade students at 37 elementary schools in Busan. The data were collected by a structured self-administered questionnaire, measuring role expectation and performance that students recognize. The data were analyzed with descriptive statistics, t-test, and ANOVA by SPSS program. The results were summarized as follows. 1. Students' level of recognizing the role expectation was high(M=4.08) and level of the role performance was moderate to high(M=3.50) within range of 1 to 5. The students recognized role expectation greater than role performance. 2. The students' point of view for role expectation and performance for school health educators were related to several characteristics of students and school health educators. Students' levels of recognizing the role expectation and performance were higher when students were male, healthy, their academic performance was high, their level of satisfaction with their school life was high, and their level of satisfaction with using school health office was high. With characteristics of School health educators, students' level of appreciating the role expectation was higher when educators were of an older age and had a long career, and when they were fairly satisfied with their job as an educator. Students' level of recognizing the role performance was higher when educators were of a younger age, and had a small number of students at school. This indicates that there exists role conflict on students and implies that the conflict needs to be mediated, and desirable solutions to address the conflict need to be developed by school health educators.

• Research in Community and Public Health Nursing
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• v.18 no.1
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• pp.123-135
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• 2007

Purpose: This study was carried out to suggest methods for improving school health promotion programs by investigating the daily activities and the performance level of environment management, the awareness of importance, and opinions on the revision of and knowledge about laws and regulations related to school health promotion programs. Method: The subjects of this study were 289 school nurses in Gyeongsangbuk-do. The survey used a questionnaire containing 90 questions developed by the present researcher. Data were collected from July 5 to July 21, 2006 and analyzed using SPSS 12.0 for Windows. Result: 1. Regular check-up and drinking water management got the highest score in performance level. Sexual health and drinking water management got the highest score in the awareness of importance. 2. School nurses were aware of laws and regulations related to their clients (0.93), and the revision opinion was high on the whole (3.58). 3. According to general characteristics, the more educated school nurse were (F=6.80, p=.001) and the fewer students their school had (F=4.66, p=.010), the higher their performance level in daily activities was. The shorter their career in their work was (F=4.86, p=.008), the fewer classes their school had (F=5.04, p=.007) and the fewer students their school had (F=3.83, p=.023), the higher their awareness of importance was. 4. There was not any difference in the performance level of environment management according to general characteristics. The awareness of importance was highest in school nurses with experience less then ten years (F=3.66, p=.027). 5. There was not any difference in knowledge about laws and regulations according to general characteristics. The revision opinion was high in school nurses at schools with less than 18 classrooms (F=6.04, p=.003) and less than 500 students (F=4.24, p=.015). Conclusion: When school nurses perform school health promotion programs actively and vigorously, the students can be healthy and national health promotion can be actualized fundamentally.

• The Journal of Korean Society for School & Community Health Education
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• v.6
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• pp.75-87
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• 2005

The purpose of this study was to describe elementary school students' health communication needs based on school-based health fairs by students' demographic characteristics and school health education experiences. A self-administered survey was conducted to a total of 851 fifth-grade students in 8 elementary schools in Seoul. For survey participant sampling, Seoul area was divided into four districts: north, south, east, and west, and two elementary schools were selected from each district by the stratified convenient sampling process. Three class 5th-grade students in each selected school finished the survey. Questionnaires and survey instruction letters were delivered to vice-principals in the designated schools and the vice-principals managed the survey process. The survey Questionnaire included demographic characteristics (sex, parent's marital status, parents' educational status, famil financial status, the person whom was with after school, and daily computer hour), health education experiences (health education at school, and school health education satisfaction), and health communication types. The health communication types were reorganized into eight types based on comprehensive literature review on health fairs (or child and adolescence. The health communication types were 'health exam and advice fair,''health promotion advertising and campaign,' 'health-related exhibition and experience fair,' 'profession visit-in-school education,' 'health-related VCR or movie festival,' 'health-related institute visits,' 'internet health counseling,' and 'telephone health counseling.' Regarding demographic characteristics, sex, family financial status, and academic performance were significant factors related to health communication need scores (p <.05). Girl, high level of family financial status, and excellent academic performance score were related to high score of health communication need. In terms of school health education experience, taking regular class for health education and satisfaction with school health education were linked to higher health communication need scores. This result discusses that experience and satisfaction with school health education largely contribute to building participants' health communication concepts and needs.

• Journal of the Korean Society of School Health
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• v.20 no.1
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• pp.25-35
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• 2007

Purpose: This study was to identify the types and characteristics of health problems of middle school students in Gangwondo. Methods: The subjects of the study were 11 middle schools from 47 schools with nurse teachers in Gangwondo. The anecdotal records of the school health clinics were collected from March to December in 1998 with the agreement of nurse teachers of the schools. Results: 71.0% of the middle students visited the school health care clinics once or more than once. The mean frequency of health problems was 2.03 times per one year. The rate of health problems did not show any statistical differences by sex, school location, age, the day of the week and weather. However, there were statistical differences of the rate by month. The highest rate was showed in September, followed by June and April (F=2.52, p=0.01). Health problems were classified into 11 types. Gastrointestinal illness showed the largest proportion (60.6%). The oral illness showed statistical differences among the location of school, between municipal and rural area (t=-2.97, p=0.016). There were 411 types of signs and symptoms recorded. Among them, headache was showed the highest proportion with 2,122 cases (11.2%). Conclusion : The incidence rate of health problems was higher than that of earlier studies. It showed that the incidence rates and the types of diseasps in middle school students were different by school locations, characteristics of students, and months. To improve the qualities of primary cares in school health services, the reformed and unified anecdotal record system and the standardized guidelines for primary care are necessary.