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경기도 초등 혁신학교와 일반학교의 교실수업형태의 차이 및 변화과정 분석
송영범(Young-Beom, Song),강경석(Kyung-Seok, Kang) 중앙대학교 한국교육문제연구소 2020 한국교육문제연구 Vol.38 No.1
본 연구의 목적은 혁신학교와 일반학교의 교실수업형태(교수자 중심, 학습자 중심)에 대한 현 실태를 분석하여 수업혁신과 공교육 개선을 위해 접근해야 할 교실수업형태에 대한 논의점과 시사점을 제시하기 위함이다. 이를 위해 다음과 같이 연구문제를 설정하였다. 첫째, 혁신학교와 일반학교간 교실수업 형태는 어떠한 차이가 있는가? 둘째, 혁신학교와 일반학교 각각의 교실수업형태는 어떠한 변화를 보여왔는가? 셋째, 혁신학교와 일반학교간 교실수업형태의 차이는 어떠한 변화를 보여 왔는가? 본 연구 결과는 다음과 같다. 첫째, 차이분석 결과, 교수자 중심 수업형태의 경우 1, 2차년도에는 일반학교가 높았던 것이 3차년도에는 유의한 차이가 없었으며, 학습자 중심 수업형태의 경우 1, 2차년도에 유의한 차이가 없었던 것이 3차년도에 혁신학교가 더 높게 나타났다. 둘째, 비조건모형 분석 결과, 교수자 중심 수업형태의 경우 혁신학교와 일반학교 모두 초기값에 유의한 차이가 있었으나, 변화율에서는 일반학교에서만 부적 변화를 확인하였다. 학습자 중심 수업형태의 경우에 혁신학교와 일반학교 모두 초기값에 유의한 차이가 있었으며, 변화율에서 일반학교만 부적 변화를 확인하였다. 셋째, 조건모형 분석 결과, 교수자 중심 수업형태의 경우 혁신학교와 일반학교간 초기값의 차이와 그 변화의 유의성을 확인할 수 있었으나, 학습자 중심 수업형태의 경우에는 초기값과 변화율 모두 유의하지 않았다. The purpose of this study is to analyze the current status of class instruction in innovative elementary schools and regular elementary schools, and to present discussion points and implications for class instruction type that should be approached in order to improve class instruction and public education. To this end, research questions were set up as follows. First, what are the differences of class instruction types between innovative schools and regular schools? Second, how have the class instruction types changed by each school? Third, how have the differences of class instruction types between innovative schools and regular schools changed? The results of this study were as follows. First, as a result of the difference analysis, in the case of teacher-centered type, regular schools were higher in the first and second years, but there was no significant difference in the third year. In the case of learner-centered type, there was no significant difference in the first and second years, but in the third year innovative schools were higher. Second, as a result of the non-conditional model analysis, in the case of teacher-centered type, there were significant differences in the initial status of both innovative and regular schools, but in the rate of change, there was negative changes in regular schools. In the case of learner-centered type, both innovative and regular schools had significant differences in initial status, and only the regular schools had an negative changes in the rate of change. Third, as a result of the conditional model analysis, in the case of teacher-centered type, there were significant differences in both the initial status and the rate of change between the innovative schools and the regular schools. In the case of learner-centered type, neither the initial status nor the rate of change were significant.
티타늄 합금 분말 소결체의 고온 변형 거동 및 미세조직 연구
김영무,송영범,이성호,권영삼,Kim, Youngmoo,Song, Young-Beom,Lee, Sung Ho,Kwon, Young-Sam 한국분말야금학회 2014 한국분말재료학회지 (KPMI) Vol.21 No.4
The effects of processing parameters on the flow behavior and microstructures were investigated in hot compression of powder metallurgy (P/M) Ti-6Al-4V alloy. The alloy was fabricated by a blended elemental (B/E) approach and it exhibited lamellar ${\alpha}+{\beta}$ microstructure. The hot compression tests were performed in the range of temperature $800-1000^{\circ}C$ with $50^{\circ}C$ intervals, strain rate $10^{-4}-10s^{-1}$, and strain up to 0.5. At $800-950^{\circ}C$, continuous flow softening after a peak stress was observed with strain rates lower than $0.1s^{-1}$. At strain rates higher than $1s^{-1}$, rapid drop in flow stress with strain hardening or broad oscillations was recorded. The processing map of P/M Ti-6Al-4V was designed based on the compression test and revealed the peak efficiency at $850^{\circ}C$ and $0.001s^{-1}$. As the processing temperature increased, the volume fraction of ${\beta}$ phase was increased. In addition, below $950^{\circ}C$, the globularization of phase at the slower strain rate and kinking microstructures were found. Based on these data, the preferred working condition of the alloy may be in the range of $850-950^{\circ}C$ and strain rate of $0.001-0.01s^{-1}$.
타이타늄 합금 분말 형상 및 치밀화 기구에 따른 미세조직 및 기계적 물성 영향 연구
김영무,권영삼,송영범,이성호,Kim, Youngmoo,Kwon, Young-Sam,Song, Young-Beom,Lee, Sung Ho 한국분말야금학회 2019 한국분말재료학회지 (KPMI) Vol.26 No.4
The objective of this study is to investigate the influence of powder shape and densification mechanism on the microstructure and mechanical properties of Ti-6Al-4V components. BE powders are uniaxially and isostatically pressed, and PA ones are injection molded because of their high strengths. The isostatically compacted samples exhibit a density of 80%, which is higher than those of other samples, because hydrostatic compression can lead to higher strain hardening. Owing to the higher green density, the density of BE-CS (97%) is found to be as high as that of other samples (BE-DS (95%) and P-S (94%)). Furthermore, we have found that BE powders can be consolidated by sintering densification and chemical homogenization, whereas PA ones can be consolidated only by simple densification. After sintering, BE-CS and P-S are hot isostatically pressed and BE-DS is hot forged to remove residual pores in the sintered samples. Apparent microstructural evolution is not observed in BE-CSH and P-SH. Moreover, BE-DSF exhibits significantly fine grains and high density of low-angle grain boundaries. Thus, these microstructures provide Ti-6Al-4V components with enhanced mechanical properties (tensile strength of 1179 MPa).
감법을 이용한 실리콘 오일 기반의 2채널 광섬유 온도 센서
이동은 ( Dong Eun Lee ),유욱재 ( Wook Jae Yoo ),신상훈 ( Sang Hun Shin ),김민건 ( Mingeon Kim ),송영범 ( Young Beom Song ),김혜진 ( Hye Jin Kim ),장경원 ( Kyoung Won Jang ),탁계래 ( Gye Rae Tack ),이봉수 ( Bongsoo Lee ) 한국센서학회 2016 센서학회지 Vol.25 No.5
We developed a 2-channel fiber-optic temperature sensor (FOTS) using a temperature sensing probe, a fiber-optic coupler, transmitting optical fiber, and an optical time domain reflectometer (OTDR). The temperature sensing probe is divided into a sensing probe and a reference probe for accurate thermometry. A sensing probe is composed of a silicon oil, a FC terminator, a brass pipe, and a singlemode optical fiber and the structure of a reference probe is identical with that of the sensing probe excluding a silicon oil. In this study, we measured the modified optical powers of the light signals reflected from the temperature sensing probe placed inside of the water with a thermal variation from 5 to 70oC. Although the optical power of the reference probe was constant regardless of the temperature change, the optical power of the sensing probe decreased linearly as the temperature increased. As experimental results, the FOTS using a subtraction method showed a small difference (i.e., hysteresis) in its response due to heating and cooling. The reversibility and reproducibility of the FOTS were also evaluated.
OTDR을 이용한 실리콘 오일 기반의 광섬유 온도 센서
장재석(Jae Seok Jang),유욱재(Wook Jae Yoo),신상훈(Sang Hun Shin),이동은(Dong Eun Lee),김민건(Mingeon Kim),김혜진(Hye Jin Kim),송영범(Young Beom Song),장경원(Kyoung Won Jang),조승현(Seunghyun Cho),이봉수(Bongsoo Lee) 대한전기학회 2015 전기학회논문지 Vol.64 No.11
In this study, we developed a fiber-optic temperature sensor (FOTS) based on a silicone oil and an optical time domain reflectometer (OTDR) to apply the measurement of a coolant leakage in the nuclear power plant. The sensing probe of the FOTS consists of a silicone oil, a stainless steel cap, a FC terminator, and a single mode optical fiber. Fresnel reflection arising at the interface between the silicone oil and the single mode optical fiber in the sensing probe is changed by varying the refractive index of the silicone oil according to the temperature. Therefore, we measured the optical power of the light signals reflected from the sensing probe. The measurable temperature range of the FOTS using a Cu-coated silica fiber is from 70℃ to 340℃ and the maximum operation temperature of the FOTS is sufficient for usage at the secondary system in the nuclear power plant.