• Korean Journal of Agricultural Science
• /
• v.40 no.4
• /
• pp.325-331
• /
• 2013

This experiment has been carried out to determine optimal culture conditions for the production of cut flowers and tubers of Calla (Zantedeschia 'Golden Affair' and 'Black Magic') in highlands. Treatments consisted of various levels of root zone environments, Results are as follows: Calla 'Golden Affair' were grown with different mulching materials such as Non-mulching, Black film, reflective film, Rice hull. Mulching materials resulted in no difference in the number of cut flowers but flower length was highest in reflective film. Calla 'Black Magic' were treated with various soil water content, soil type and watering time. Number of cut flowers and flower quality were greatest when the plants were watered at -80 kPa soil water content. No symptoms of soft rot (Erwinia carotovora) was observed at this soil water content. The occurrence of soft rot was observed with similar percentage according to soil type and the soil water content. When Calla 'Black Magic' were watered at the time of soil surface drying, growth was greater compared to others. Air temperature and PPF affected plant growth and photosynthesis. Photosynthetic rate was greatest at $25^{\circ}C$ and PPF $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, while lowest at $28^{\circ}C$ and PPF $800{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Soft rot did not occur without regard to dipping treatment (0, 5, 10, 24, 48 hours) when the day and night temperature were maintained at $25^{\circ}C$ and $20^{\circ}C$, respectively.

• Journal of The Korean Association For Science Education
• /
• v.43 no.3
• /
• pp.191-207
• /
• 2023

In this study, we comprehensively investigated the cases of science teachers who implemented NOS assessments in Science Inquiry Experiment. Two science teachers working at high schools located in Seoul who taught and assessed NOS in Science Inquiry Experiment according to the 2015 revised curriculum participated in the study. We collected lesson and assessment materials and observed NOS lessons and assessments. We also conducted interviews. Based on the collected data, we analyzed the processes of the teachers' NOS assessments. The analyses of the results revealed that the teachers constructed the assessments by themselves due to a lack of NOS assessment experience and related materials. They had difficulties in selecting an appropriate assessment method and constructing assessment questions and criteria. Both teachers found it difficult to assess an understanding of NOS because it concerns the subjective views of individual students. Therefore, they had difficulties in setting detailed assessment criteria, which also led to difficulties in the overall assessment process. There was a difference in the reflective level of the assessments between the two teachers. In the reflective activities of low levels, the assessments were not properly enacted because it was difficult to infer students' understanding. Orientation toward teaching NOS influenced the perceptions of NOS assessment and overall lessons, resulting in a difference in NOS assessments. Finally, the absolute evaluation of Science Inquiry Experiment also affected teachers' NOS assessments. Based on the above results, implications for effective NOS assessments in schools are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.535-536
• /
• 2008

Multi-layered thin films of ZnS/$Na_3AlF_6$/ZnS/Cr were deposited on glass substrate by evaporation process. ZnS and $Na_3AlF_6$ were selected as high and low refractive index material, and additionally Cr was chosen as mid reflective layer respectively. The multi-layered thin films were prepared in terms of different optical thickness and different staking sequence and layers. The optical properties were systematically characterized with different optical thickness of $Na_3AlF_6$ especially $0.25\lambda$ and $0.5\lambda$. In order to expect the experimental result, the simulation program, the Essential Macleod Program(EMP) was adopted. Based on the results taken by spectrophotometer at viewing angle $45^{\circ}$, the ZnS/$Na_3AlF_6$/ZnS/Cr multi-layered thin film shows purple colour range in $0.25\lambda$， bluish green in $0.5\lambda$, red purple in $0.75\lambda$, and purple in $1.0\lambda$ respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.37 no.2
• /
• pp.182-187
• /
• 2024

Currently, the most developed new energy source is solar energy. Because solar power is installed outside, it is exposed to many pollutants. Pollutants are causing the characteristics of solar energy to deteriorate. Therefore, this study aims to develop a water-repellent coating to prevent contamination of solar modules. Silica and Titania materials are mainly used as water-repellent coating materials. In this study, it was based on silica and the contact angle characteristics were measured according to the change in the amount of silica and ammonia water added and the number of coatings. As a result of the measurement, it was confirmed that the contact angle was more than 60 degrees when 0.5 mol of TEOS was added to 50 mL and 0.15 M when 1 mL of ammonia water was added to 296.47 ml of distilled water. And it was confirmed that the contact angle improved when the number of coatings was applied twice. A water-repellent coating material was applied to low iron tempered glass used to protect dye-sensitized solar cell modules. The characteristics of the module were measured after spraying DI-Water on low-emission tempered glass with a water-repellent coating. As a result of the measurement, the efficiency of the module without application, the efficiency of the module coated once, and the module coated twice were 4.87%, 4.90%, and 4.91%, respectively. It was confirmed that the efficiency of the module increased by applying water-repellent coating. As a result of this study, it is determined that the water-repellent coating material will help improve solar power generation efficiency and lifespan by being self-cleaning and non-reflective.

• East Asian mathematical journal
• /
• v.28 no.4
• /
• pp.383-401
• /
• 2012

The purpose of mathematics education includes two important areas; cognitive area that emphasizes mathematical knowledge and understanding and affective area that stresses mathematical interest and attitude. The purpose of mathematics education is not only in acquiring the contents and knowledge but also rousing up interest and attention toward mathematics. Therefore, effort to accomplish this affective purpose has to be made. Introducing history of mathematics to teaching can be a important method for the students to arouse interest and attention toward mathematics. History of mathematics can help the students who are familiar to only manipulation of the symbols to develop a new way of thinking and mathematical thoughts arousing reflective thinking. According to the survey, although the effect of using mathematics history has been recognized, the mathematics history has neither been developed as teaching materials nor reflected in the courses of study. The purpose of this research is to develop the reading materials into suit for the mathematics curriculum to extract contents of the mathematics valuable in using in elementary mathematics teaching, and to investigate the effect of reading materials using the history of mathematics on learning attitude in elementary school. The way of developing materials in this study is as follows. First, to select the interesting and instructive subject for the elementary students such as the story and life of a mathematician, developmental stages of mathematical theory and calculation currently used and finding the patterns of the rules that requires mathematical thoughts. Second, to classify the selected items according to mathematics curriculum. Third, to reorganize the classified items of the appropriate grade with the reading materials of dialogue pattern in order to draw attention and interest from the students I developed 18 kinds materials in accordance with the above procedure and applied 5 materials among them to one class in 4th grade. Analysing the student's responses, First, using history of mathematics helps the students to arouse interest and confidence on mathematical learning attitude. And the students became better attitude of studying by oneself and attention on class. Second, as know by opinions after lesson, most students have a chance refresh one's thinking of mathematics, want to know the other content of history of mathematics and responded to study hard in mathematics. As a result, the reading materials on the basis of the history of mathematics motivates students for mathematics and helps them become confident in mathematics. If the materials are complemented properly, they will be useful and effective for students and teachers.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.1
• /
• pp.227-238
• /
• 2022

This study is the case of non-face-to-face teaching-learning in the subject of "Research and Guidance on Early Childhood Materials" in the pre-child teacher training program. The study conducted a non-face-to-face teaching-learning model for 18 students at B University in region C who took lectures on 'Research and Guidance on Early Childhood Materials' in the first semester of 2021. As a non-face-to-face teaching-learning model, it consisted of video lectures, real-time zoom classes, and various forms of 'communication' through frequent feedback and interaction and 'participation'. As a teaching-learning strategy for the participation of pre-service early childhood teachers, comment on questions related to early childhood materials, in-depth reflection on early childhood materials through writing reflective journals and observation reports, and step-by-step presentation of making childhood materials plans, processes, and results were carried out. As a result of exploring the experience of making early childhood materials for pre-service early childhood teachers, factors such as "growth experience through trial and error," "thinking from child's point of view", "Increase efficiency and reduce burden through communication", "Process rather than result" and "The importance of communication and interaction in non-face-to-face classes"

• Journal of The Korean Association For Science Education
• /
• v.37 no.2
• /
• pp.347-358
• /
• 2017

The purpose of this study is to research on the professional development of pre-service chemistry teachers in terms of personal practical knowledge(PPK), and draw a discussion for pre-chemistry teacher education. A reflective discussion through a Community of Practice(CoP) activity has been conducted with 5 pre-service chemistry teachers studying in a college of education located in Seoul. The analysis of the results reveals that 'Subject-matter knowledge' is leaning toward massive chemical contents, 'Curriculum knowledge' is below the level of selecting, analyzing, and applying curriculum materials. 'Instruction knowledge', especially the knowledge of chemistry experiment and research, is not enough to lead secondary students' scientific experiment. 'Milieu of school knowledge' is stunted in growth for the reason of communication-deficiency between a college of education and a community, and among education- related groups. 'Self-knowledge' has been diminished not only because there is a bad influence from college classmates not wanting to be a teacher, but also a lack of communication in the chemistry-education department which can make pre-teachers' belief strong. In conclusion, it is especially needed for the chemistry-education department to strengthen pre-teachers' 'Self-knowledge' in order to develop PPK. This study suggests operating 'a professional community' that has a periodic meeting with pre-service teachers, teachers, professors, community people, education practitioners, and researchers. In addition, it would be effective for increasing pre-teachers' PPK to reconsider depth and direction of 'Subject-matter knowledge', to give an opportunity to examine curriculum materials critically and reorganize them, to improve the course of chemistry experimental subject to the way of improving pre-teachers' leadership in chemistry inquiry experiment, and to raise the quality of educational service activities.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2014-2016
• /
• 2004

In order to obtain a low-loss ferroelectric phase shifter, the reflection-type phase shifter with ferroelectric defected ground structure (DGS) resonators has been designed in this paper. The proposed phase shifter is consist of a 3-dB $90^{\circ}$ branch-line hybrid coupler and terminated reflective circuit with tunable ferroelectric DGS resonator. The ferroelectric DGS unit structure can provide high Q resonator characteristic at high frequencies. The design parameters of equivalent circuit for the tunable DGS resonator are derived by using simple circuit analysis method and three-dimensional full wave finite element method. The fabricated phase shifter has an insertion loss of better than 3.4dB at 13.5GHz.

• The Research Journal of the Costume Culture
• /
• v.28 no.2
• /
• pp.245-264
• /
• 2020

This study identifies Kim Jihaye and Lee Jeanyoun as actor-networks with cultural values and meanings. It analyzes the process of reorganizing their works into Korean orientalism via an action of co-construction with formative techniques. First, the historical context of orientalism formed in the fashion world will be studied, followed by the design characteristics of orientalism, and the correlation between the Korean orientalism of these designers on the world stage influenced by the globalization discourse of Korean tradition since the 1980s. Next, works of Kim Jihaye and Lee Jeanyoun from 2000 to 2012 will be analyzed, revealing aspects of Korean image reproduction. Consequently, this study finds that the Korean image is restructured socio-culturally through technological imagery as a reproduction of reality by the production subject. This study reminds us of the reflective and cultural meaning of fashion designers in the area of image reproduction, sociocultural practice, and materials and technology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.7
• /
• pp.584-588
• /
• 2009

Layered ZnS/$CaF_2$/ZnS/Cu film was deposited on glass substrate by using evaporation method. ZnS and $CaF_2$ were chosen as high and low refractive materials. Cu was used as mid-reflective layer. Reflectance with different optical thickness of $CaF_2$ ranging from $0.25{\lambda}\;to\;0.5{\lambda}$ were systematically investigated by using spectrophotometer. In order to expect the experimental results, the simulation program, the Essential Macleod Program(EMP) was adopted and compared with the experimental data. Based on the results taken by spectrophotometer, the ZnS/$CaF_2$/ZnS/Cu multi-layered thin film show the maximum reflectance of 80% at 625nm $(0.25{\lambda}\;in\;CaF_2)$ and 42% at 660nm $(0.5{\lambda}\;in\;CaF_2)$ respectively. As compared with the experimental results and simulation data, it was confirmed the experimental data is well matched with the EMP data.