• Journal of the Korean earth science society
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• v.25 no.6
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• pp.391-401
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• 2004

This study has developed the software to enhance the level of spatial perception of geological structure for high-school students. And it is examined the effects after applying in high school. The contents of the software are compose of the two elements (space direction, space visualizing) forming spatial concepts in the structure geology. The program was applied to the 60 high school students of 4 high schools in the Gyeonggido. And we interviewed with 4students of the study group to obtain the variation of the geology spatial concept. As a result of appling, the geology spatial concept level enhanced significantly (p < 0.05). And the result of interview for 4 students using the program showed more enhanced achievement for the students through the process of space visualizing.

• Journal of Power Electronics
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• v.4 no.3
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• pp.138-151
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• 2004

In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.740-749
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• 2002

The purpose of this study was to survey junior high school teachers' and students' perceptions on the science textbooks. Subjects of this study were 113 science teachers and 715 students from junior high schools in Daegu and Kyungpook area. As statistical method, one-way ANOVA and t-test were used to check differences of the perceptions between teachers and students. Teachers had different perceptions by school location and class size, while students had different perceptions by school location, co-ed, class size, and grade level. Both teachers and students having the relativistic viewpoint on textbook knowledge regarded the knowledge as relativistic one, and preferred the student-centered textbooks. Teachers liked textbooks written by the student-centered view more than students did. Teachers had the more absolutistic viewpoint on textbook knowledge and on teaching, while students liked the electronic textbooks more than teachers did.

• Journal of the Korean Society of Earth Science Education
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• v.1 no.1
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• pp.72-84
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• 2008

This study is focused on the main concepts of gravity and geomagnetics which are introduced in the earth science textbooks of high school in 7th curriculum. This study examines the validity and accuracy of the Earth Science textbooks and shows some effective teaching plans by using the latest materials. This study also illustrates the main concepts of gravity and geomagnetics through presenting some effective and practical teaching-learning methods. The results of the study were as follows: First of all, a number of main concepts of six textbooks of high school were selected; the field of gravity, the direction and dimension of gravity, the measurement of gravity, the main reason of gravity anomaly and geoid, earth terrestrial magnetic field, secular variation of goemagnetics. Secondly, most Earth Science textbooks of high school explains the main concepts of the gravity and geomagnetics in similar ways. Those textbooks, however, don't put an emphasis on the essential contents which has been regarded as important thing in terms of the current educational course of study. The high school textbooks also use the material which is too old-fashioned and has some problems of accuracy and validity. Especially, many main concepts of the textbooks and scientific data(such as the direction of gravity, the measurement of gravity, the main reason of gravity anomaly, the use of geoid, secular variation) are different with those of South Korea, In addition, some materials(graphs and diagrams) are very old ones and they don't have authentic information.Finally, Among the various main concepts, some important ideas (the direction of the gravity and the method of measuring gravity, the measurement and use of gravity anomaly, the definition of geoid and secular variation of geomagnetics) should be corrected by showing the latest and authentic materials.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.475-476
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• 2006

Recently, the demand for high density MOSFET arrays are increasing. In implementing 3-D devices to this end, it is inevitable to ion-implant vertically in order to avoid screening effects caused by high silicon fins. In this study, the dependency of drain current characteristics on doping profiles is investigated by 3-D numerical analysis. The position of concentration peak (PCP) and the doping gradient are varied to look into the effects on primary current characteristics. Through these analyses, criteria of ion-implantation for 3-D devices are established.

• Journal of The Korean Association For Science Education
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• v.33 no.1
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• pp.17-29
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• 2013

High school 'science' in the 2009 revised curriculum in Korea was developed for the purpose of enhancing students' scientific literacy needed for citizenship in a democratic society. For this analysis, 'science' includes a variety of scientific topics from the origin of the universe to the birth of life, and the relationship between technology and modern society. It aims to make students understand the process of scientific inquiry and foster interest and curiosity about science. On the other hand, interest has been studied as a psychological construct to affect academic achievement and career selection of students. In this study, the authors investigated students' interest in high school 'science' in view of the 2009 revised curriculum. To carry this out, a survey tool was developed according to previous research, with 997 high school students' responses analyzed with descriptive statistics and factor analysis. The result showed that the students' interest in high school 'science' in view of the 2009 revised curriculum can be interpreted into three dimensions such as motivation, activity, and topic, which has several sub-dimensions. Students' interest in motivation dimension was higher than in activity or topic dimension, while the average value was slightly higher than the middle value. They showed different distribution of interest by gender and job orientation, especially in activity and topic dimensions. From this study, the authors can infer the multi-dimensional property of students' interest in high school 'Science' and the different distribution of interest by dimensions.

• Proceedings of the Korea Crystallographic Association Conference
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• 2007.11a
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• pp.39-39
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2015.11a
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• pp.145-146
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• 2015

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.307.2-307
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• 2001

• Proceedings of the Korean Magnestics Society Conference
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• 2014.11a
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• pp.53-54
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• 2014