• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.84-91
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• 2003

Flow-Induced Vibration of steam generator tubes may result in fretting wear damage at the tube-to-support locations. KSNP(Korean Standard Nuclear Power plant) steam generators experienced fretting wear in the upper part of U-bend above the central cavity region of steam generators. This region has conditions susceptible to the flow-induced vibration, such as high flow velocity, high void fraction, and longer unsupported span. To improve its performance, APR1400 steam generator is designed with additional supports in this region to reduce unsupported span and to reduce peak velocity in the central cavity region. In this paper, we examined its performance improvement using ATHOS code. The thermal-hydraulic condition in the region of secondary side of APR1400 steam generator is obtained using the ATHOS3 code. The effective mass for modal analysis is calculated using the void fraction, enthalpy, and operating pressure information from ATHOS3 code result. With the effective mass distribution along the tube, natural frequency and mode shape is obtained using ANSYS code. Finally, stability ratios and real mean squared displacements for selected tubes of the APR1400 steam generator are computed. From these results, the current design of the APR1400 steam generator are examined.

• Journal of the Korean Society of Earth Science Education
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• v.5 no.3
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• pp.297-306
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• 2012

The purpose of this study was to examine the effects of science-based STEAM astronomical learning program on space perception ability and scientific attitudes. For this study the 5 grade, 2 class was divided into a research group and a comparative group. The class was pre-tested in order to ensure the same standard. Space perception ability test and scientific attitudes test was used to find the effect of the science-based steam astronomical learning program. And the results were analyzed by spsswin 18.0. The results of this study were as follows. First, the science-based STEAM astronomical learning program was a positive effects on space perception ability of elementary students. Second, the science-based STEAM astronomical learning program was a positive effects on scientific attitudes of elementary students. According to this research, the science-based STEAM astronomical learning program was verified to improve space perception ability and scientific attitudes on the elementary students.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.2
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• pp.226-233
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• 2014

This study is to develop a subject substitute STEAM program which can be applied instead of classes in school field and to seek development plan of a subject substitute STEAM program based on that. The program was developed by experts on science education and teachers who participated in developing STEAM program business conducted by the Korea Foundation for the Advancement of Science and Creativity and one 6th grade located in small and medium city was chosen for application. As a result, the subject substitute STEAM program attracted students' interest and helped to understand for them. In addition, the development plan was found that teachers' participation is very important, an inquiry activity related to real life is to be included and enough activity time is helpful in students' understanding, when developing a subject substitute STEAM program.

• Journal of The Korean Association For Science Education
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• v.32 no.6
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• pp.1072-1086
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• 2012

Science, Technology, Engineering, and Mathematics (STEM) education in the U.S. has been identified as a significant national reform in K-16 education and curriculum in order to prepare students for the global economy of the 21st century. Korea has been facing very similar challenges to improve science, technology and mathematics education, in particular, the affective aspect of learning science and mathematics. Science, Technology, Engineering, Arts, and Mathematics (STEAM) education has become a crucial issue in Korean education system. The major purpose of this exploratory study is to inform the exemplary framework of STEAM education in the U.S. for Korea and to provide descriptive and analytical accounts on STEAM teaching and learning as an innovative integrated convergence education. This study integrates the outcomes of research papers on STEM education and recent literature. It employs content analysis methodology qualitatively by analyzing and synthesizing the findings, conclusions, discussions, and recommendations of accumulated research works related to STEM/STEAM education. This study will help gain a stronger sense of the STEAM framework and will guide to develop the educational programs for Korea.

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.343-352
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• 2006

Convenient analytical tools for evaluation of the aperiodic and the fluctuating instabilities of the passive residual heat removal system (PRHRS) of an integral reactor are developed and results are discussed from the viewpoint of the system design. First, a static model for the aperiodic instability using the system hydraulic loss relation and the downcomer feedwater heating equations is developed. The calculated hydraulic relation between the pressure drop and the feedwater flow rate shows that several static states can exist with various numbers of water-mode feedwater module pipes. It is shown that the most probable state can exist by basic physical reasoning, that there is no flow rate through the steam-mode feedwater module pipes. Second, a dynamic model for the fluctuating instability due to steam generation retardation in the steam generator and the dynamic interaction of two compressible volumes, that is, the steam volume of the main steam pipe lines and the gas volume of the compensating tank is formulated and the D-decomposition method is applied after linearization of the governing equations. The results show that the PRHRS becomes stabilized with a smaller volume compensating tank, a larger volume steam space and higher hydraulic resistance of the path $a_{ct}$. Increasing the operating steam pressure has a stabilizing effect. The analytical model and the results obtained from this study will be utilized for PRHRS performance improvement.

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.391-398
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• 2006

It is recommended to clean steam generators of nuclear power plants during plant outages. Under normal operations, sludge is created and constantly accumulates in the steam generators. The constituents of this sludge are different depending on each power plant characteristics. The sludge of the Kori Unit 1 steam generator, far example, was found to be composed of 93% ferrous oxide, 3% carbon and 1% of silica oxide and nickel oxide each. The research to develop a lancing system that would remove sludge deposits from the tubesheet of a steam generator was started in 1998 by the Korea Electric Power Research Institute (KEPRI) of the Korea Electric Power Corporation (KEPCO). The first commercial domestic lancing system in Korea, the $KALANS^(R)-I$ Lancing System, was completed in 2000 for Kori Unit 1 for cleaning the tubesheet of its Westinghouse Delta-60 steam generator. Thereafter, the success of the development and site implementation of the $KALANS^(R)-I$ lancing system for YGN Units 1&2 and Ulchin Units 3&4 was also realized in 2004 for sludge removal at those sites. The upper bundle cleaning system for Westinghouse model F steam generators is now under development.

• Journal of The Korean Association of Information Education
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• v.17 no.4
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• pp.487-496
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• 2013

This study examined the effects of STEAM program using authoring tool on elementary school students' creative personality and science-related attitude. For this study, after analyzing curriculum from the first term of 6th grade and extracting the learning elements and topic, I developed lesson plans and App contents. As a result of applying STEAM program using Storyline to 6th grade elementary school class. dividing two groups-experimental group, comparison group-for this study, tested t-test, the test result of experimental group got a meaningful result statistically. There was positive effect on improving elementary school students' creative personality and science-related attitude.

• Korean journal of food and cookery science
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• v.32 no.2
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• pp.204-210
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• 2016

Purpose: This study analyzed and compared the physico-chemical and affective properties between mackerels cooked by an electric pan and under superheated steam. Methods: Mackerel were cooked by an electric pan ($95^{\circ}C$) for 10 min and mackerel cooked under superheated steam ($250^{\circ}C$) for 5 min to be internal temperatures of $75{\pm}5^{\circ}C$ and tests to measure proximate composition, color values, texture profiles, microorganism counts and sensory acceptance were performed. Results: The moisture contents were 60.30% and 73.81% in mackerels cooked by electric pan and under superheated steam, respectively. The rate of weight loss in mackerel cooked by electric pan was 39%, whereas it was 29% in mackerel cooked under superheated steam. Mackerel cooked under superheated steam exhibited more yellowness, higher springiness, cohesiveness, gumminess, chewiness, and resilience with more acceptable preferences (appearance, odor, taste, and texture) compared to the mackerel cooked by electric pan. Conclusion: The application of superheated steam technology to fish products could reduce the cooking time and nutritional loss. Also, it could produce highly preferred fish products compared to that prepared by conventional electric pan.

• Journal of Korean Elementary Science Education
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• v.33 no.3
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• pp.510-523
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• 2014

Modern society is rapidly changing in the fields of science and technology, with new information and knowledge constantly being discovered. So enhancing the creativity and positive attitude of students is important. STEAM education enables students to develop their creativity, personality, intelligence and sensitivity with a well-balanced curriculum. In this study, considering the student's interest, a theme-centered STEAM program was developed in the 'Strata and Fossils' unit of elementary 4th grade science. The purposes were to find the impact on the academic achievement, creative problem solving abilities, and scientific attitude of elementary school students. The STEAM program are composed of contents which can be applied effectively indoors. As application results for STEAM program to J elementary school's students in J province, the experimental group increased significantly in the academic achievement, creative problem solving abilities and scientific attitude compared to the control group. Therefore, it is necessary to be developed continuous and systematic STEAM programs in units of various subjects to improve the students' academic achievement, creative problem solving abilities and scientific attitude.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.235-242
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• 2018

Hydrogen can be produced by reforming reaction of natural gas (NG) and biogas, or by water electrolysis. In this study, hydrogen production through water-electrolysis needs superheated steam above $700^{\circ}C$ for high efficiency. The production method of hydrogen like this was recommended for the 4-type processes for superheated steam ($700^{\circ}C$, 3 atm) by Bio-SRF combustion furnace. The 4-type processes to produce superheated steam at $700^{\circ}C$ from the heat source of SRF combustion furnace was simulated using PRO II. The optimum process was selected through exergy analysis. The difference of process 1 and 2 is to the order of depressure and heating process to change $180^{\circ}C$ and 7 atm to $700^{\circ}C$ and 3 atm. Process 3 and 4 is to utilize 25% of steam to generate superheated steam and remaining to use for the power generation by steam generator.