• Journal of Science Education
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• v.46 no.1
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• pp.93-108
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• 2022

The purpose of this study is to develop a STEAM program that can be used in the high school credit system to be fully implemented in 2025, and to examine its validity and effectiveness. The STEAM program analyzed the 2015 revised curriculum centering on science, technology, and engineering through the 2015 revised curriculum analysis, and then selected the five latest issues: hydrogen fuel, climate crisis, data science, appropriate technology, and barista. In accordance with this self-developed program development format (frame), it was developed for seven months through a process of group deliberation. The draft of the STEAM program for 29 sessions of five types, developed to indirectly experience the career path and occupation of high school students, was verified through consultation with 2 STEAM education experts. It was applied at five different high schools for a pilot implementation. As a result of the pilot application, it was confirmed that the students' STEAM attitude significantly improved in the post-test than the pre-test, and the students' high satisfaction with the program was confirmed. In addition, through an interview with the pilot application teacher, it was positively evaluated that 'the content and level of the program are suitable and through experience solving real-life problems, you can apply the content knowledge of related subjects and have an opportunity to experience careers.' Based on the results of the pilot application, the high school credit system STEAM program for students and teachers was finally completed in 29 lessons of five types. Through this study, the development and operation of the next-generation STEAM program that can be applied in the high school credit system should be actively developed, and a plan to improve teachers' professionalism so that the high school credit system can be established and operated properly for blended classes triggered by COVID-19. The necessity of design was suggested. This study is expected to be used as basic data for the development and operation of STEAM programs in the high school credit system, which will be fully implemented in 2025.

• Journal of The Korean Association For Science Education
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• v.24 no.2
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• pp.234-240
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• 2004

The main purpose of this study was to examine the effects of interpretive style reading materials on high school students philosophical viewpoints on science. Subjects for this study were 137 girl students in four classes of a high school located in Daejeon city. The classes were divided into two groups: experimental groups and control groups. Students in the experimental groups were administered a series of the reading materials over thirty-six sessions. Additionally, PPP(Philosophical Perspectives Prove) was used in order to assess students philosophical viewpoints on science. Results of the study showed that the interpretive style reading materials takes effect on the change of students philosophical viewpoints on science. At the initial stage, a number of students exhibited viewpoints inclined toward inductivism. As time goes by, however, viewpoint of inductivism was decreased and view of falcificationism and view of relativism were increased. The results also indicated that the effect of intervention was stable.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.393-398
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• 2014

A highly efficient dual-mode linear CMOS stacked-FET power amplifier (PA) is implemented for 3G UMTS and 4G LTE handset applications. High efficiency is achieved at a backed-off output power ($P_{out}$) below 12 dBm by employing an active-bypass amplifier, which consumes very low quiescent current and has high load-impedance. The output paths between high- and low-power modes of the PA are effectively isolated by using a bypass switch, thus no RF performance degradation occurs at high-power mode operation. The fabricated 900 MHz CMOS PA using a silicon-on-insulator (SOI) CMOS process operates with an idle current of 5.5 mA and shows power-added efficiency (PAE) of 20.5%/43.5% at $P_{out}$ = 12.4 / 28.2 dBm while maintaining an adjacent channel leakage ratio (ACLR) better than -39 dBc, using the 3GPP uplink W-CDMA signal. The PA also exhibits PAE of 35.1% and $ACLR_{E-UTRA}$ of -33 dBc at $P_{out}$ = 26.5 dBm, using the 20 MHz bandwidth 16-QAM LTE signal.

• Journal of The Korean Association For Science Education
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• v.12 no.3
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• pp.109-118
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• 1992

In this study, the attitudes of about 1200elementary and secondary students towards sciences lessons and scientists were investigated. For the survey of this study, simillar numbers of students in Seoul were selected from the 5th, 8th and 11th grades and from both sexes. For the attitudes towards science lessons, in the survey questionnaire, there were questions on the type of science lesson which students prefer and on student's assessment of science lessons which they receive. For the attitudes towards scientists, there were questions on scientists whom students respect, on students assessment of scientists and on students assessment of themselves. Results of this study can be summarized as follows: (1) A great majority of students prefered the laboratory-based to classroom-based lessons, but this tendency was less apparent in olderstudents.More boys, compared with girls, prefered laboratory-based study. (2) The student's assessment of science lessons was positive in the elementary school, neutral in the middle school and negative in the high school level. Boys showed more positive attitudes towards the study of science. (3) Apparently more girls than boys mentioned Madam Curie as a scientist whom they respect, Students tended to respect scientists in terms of their personalities rather than their cognitive abilities. (4) Students tended to assess that scientist's are more able than themselves in cognitive areas while themselves are better in affective areas. The gap between student's asessments of scientists and that of themselves became bigger in high school students. The gap between boy's assessments of themselves and girl's assessments of themselves was bigger in high school level than in middle school. (5) The decline of students attitude towards science lessons was bigger than their attitude towards scientists.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1203-1204
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• 2006

Cu-$TiB_2$ nanocomposite powders were synthesized by combining high-energy ball-milling of Cu-Ti-B mixtures and subsequent self-propagating high temperature synthesis (SHS). Cu-40wt.%$TiB_2$ powders were produced by SHS reaction and ball-milled. The milled SHS powder was mixed with Cu powders by ball milling to produce Cu-2.5wt.%$TiB_2$ composites. $TiB_2$ particles less than 250nm were formed in the copper matrix after SHS-reaction. The releative density, electrical conductivity and hardness of specimens sintered at $650-750^{\circ}C$ were nearly 98%, 83%IACS and 71HRB, respectively. After heat treatment at 850 to $950^{\circ}C$ for 2 hours under Ar atmosphere, hardness was descedned by 15%. Our Cu-$TiB_2$ composite showed good thermal stability at eleveated temperature.

• Journal of Microbiology and Biotechnology
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• v.32 no.12
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• pp.1589-1598
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• 2022

Microfibrillated cellulose (MFC) is a valuable material with wide industrial applications, particularly for the food and cosmetics industries, owing to its excellent physiochemical properties. Here, we prepared high-solid microfibrillated cellulose (HMFC) from the centrifugation of Gelidium amansiiderived MFC right after fibrillation. Dispersion properties, morphology, and structural changes were monitored during processing. HMFC has a five-fold higher solid concentration than MFC without significant changes to dispersion properties. SEM images and FTIR spectra of HMFC revealed a stable surface and structure against centrifugal forces. HMFC exhibited 2,2'-azino-bis (3-ethylbenzothiazoline6-sulfonic acid) (ABTS) radical scavenging activity, although it could not scavenge 2,2-diphenyl-1- picrylhydrazyl (DPPH). Moreover, HMFC inhibited the generation of LPS-induced excessive nitrite and radial oxygen species in murine macrophage RAW264.7 cells. Additionally, HMFC suppressed LPS-induced Keap-1 expression in the cytosol but did not alter iNOS expression. HMFC also attenuated the UVB-induced phosphorylation of p38, c-Jun N-terminal kinase (JNK) 1/2, and extracellular-signal-regulated kinase (ERK) 1/2, as well as the phosphorylation of c-Jun in the immortalized human skin keratinocyte HaCaT cells. Therefore, the application of centrifugation is suitable for producing high-solid MFC as a candidate material for anti-inflammatory and antioxidative marine cosmeceuticals.

• Journal of the Korean Institute of Educational Facilities
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• v.15 no.3
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• pp.52-58
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• 2008

• The Research Journal of the Costume Culture
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• v.22 no.6
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• pp.899-910
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• 2014

The purpose of this study was to analyze high school students' school uniform wearing attitude by group according to clothing attitude targeting Gyeongnam area. This study aims to provide preliminary data in the field of school uniform and marketing that clothing propensity by groups is considered. This study conducted a survey targeting 762 high school students in Gyeongnam. For statistical analysis, SPSS for Window 14.0 was used for frequency analysis, factor analysis, reliability analysis, multiple sponse analysis, cluster analysis, ANOVA analysis and Duncan's ex-post analysis method. As a result of cluster analysis on the clothing attitude, students were divided into 4 segmentation of fashion seeking group, fashion indifference group, conformity group and modesty group. As a result of verification on the difference in perception toward wearing school uniform by groups which were classified according to the propensity of clothing attitude, activity, stability, and practicality were all varied according to the propensity of clothing attitude. 4 groups were significant differences in the degree of consent to wearing school uniform, price of school uniforms, tendency to prefer famous brand when purchasing school uniform, experience of transforming school uniform, opinion about school uniform modification and reason for school uniform modification. While low graders were many in 'modesty group', upper graders were many in 'fashion seeking group', which means that more segmentalized satisfaction of clothing by group may be raised if such a fact is considered when planning clothing for high school students segmentalized by age.

• Journal of the Korean Society of School Health
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• v.20 no.1
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• pp.45-52
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• 2007

Purpose: The purpose of this study was to examine the types of school accidents and their first aids at Elementary, Middle, High Schools in a local area. Methods: The subjects were 1062 students who have had episodes of school accidents from 730 (Elementary = 429, Middle = 188, High = 113) schools in Chungnam province from January to December, 2006. Data were collected from accident-related record from school nurse and 'School Safety Fund', and analyzed using the SPSS Version 13.0 programs and the results and conclusions are as follows: Results: The proportion of school accidents occurred were in middle(0.43%), high(0.35%), primary(0.30%) school students. And the most frequent type of accident was fracture and then sprain. Most school accidents broke out in playground during resting time, and followed by physical education class. The most frequent cause of school accidents was carelessness and first aid was fixation the injury. Conclusion: Based on these findings, school-based and continuous safety education programs and emergency care system within school and in community can be suggested in collaboration with health-related resources. Further longitudinal study to identify causes and kinds of school accidents and can also be recommended.

• Journal of The Korean Association For Science Education
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• v.19 no.2
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• pp.293-304
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• 1999

A Calculator-Based Laboratory (CBL) system was introduced to science teachers and their perceptions to its classroom application was assessed. A CBL survey instrument was responded by 54 middle and high school science teachers who undertook a three-hour workshop of science experiments with CBL system. There were significant differences in teachers perceptions to CBL system among gender, school level, school location, teacher's degree, and years of teaching in terms of learning CBL system, applicability of CBL system for science classrooms, and effects on science achievement. Male teachers showed significantly (p<.05) higher agreement to learning of CBL system and applicability for science classrooms than female teachers. Compared to middle school teachers, high school teachers showed significantly (p<.05) high interests in CBL applicability for science classrooms and perceptions that there will be an increase of science achievement. Teachers with 4-8 years of teaching experience also showed significantly (p<.05) higher interest toward learning CBL system and its applicability. It was concluded that science teachers perceived CBL system as a promising science teaching method in Korean middle and high schools. However, a science teacher inservice training program for CBL system should be developed in consideration of gender, school level, school location, and years of teaching.