自己主導적 科學探究活動이 中等學生의 메타認知, 科學의 本性 및 科學者에 대한 認識에 미치는 影響

고용철 제주대학교 대학원 2015 국내박사

This study, through pre-to-post comparison, attempted to find out the effect of self-directed scientific research activities by team on schoolers’ meta-recognition, nature of science and perception about scientists after they were instructed to develop and further those activities. The study investigated what effects self-directed scientific research activities would have on schoolers’ meta-cognition. First, the pre-to-post test of all schoolers resulted in a statistically significant difference. Second, the same test of planning ability for meta-cognition did not result in a significant difference and thus it is thought that self-directed scientific research activities have no effect on the change of planning ability. Third, a significant difference between before and after the activities appeared in monitoring ability and thus it is thought that self-directed scientific research activities have a positive effect on the change of monitoring abilities. When middle and high schoolers, as well male and female schoolers, classified, middle schoolers and female schoolers showed a significant difference, but the rest of groups not. The study also investigated the nature of science by VOSTS questionnaire and conducted analysis to find out what effects self-directed scientific research activities have on the understanding of the nature. Among sub-factors concerning the nature of science, the score of a pre-test turned out from highest to lowest as follows: theoretical hypothesis, verification of scientific inference, scientific decision-making, scientific method, temporality of scientific knowledge, theory-dependency of observation, social construction of scientific theory, epistemological status of scientific knowledge, and scientific prediction; and the score of a post-test turned out from highest to lowest as follows: theoretical hypothesis, scientific decision-making, verification of scientific inference, temporality of scientific knowledge, scientific method, theory-dependency of observation, social construction of scientific theory, epistemological status of scientific knowledge, and scientific prediction. In the degrees of pre-to-post change, epistemological status of scientific knowledge increased by the greatest deal, followed by temporality of scientific knowledge, theoretical hypothesis, and scientific decision-making in order. In a while, verification of scientific inference was not changed between before and after the activities; and even reduction was found in scientific prediction and social construction of scientific theory. Furthermore, the study investigated schoolers’ perception about scientists by multiple-choice questionnaire and Draw-A-Scientist Test Checklist(DAST-C). In the result of multiple-choice questionnaire, first, a pre-test resulted in positive perception about scientists in 11 questions among 12 questions, but a post-test did in all questions. Among total 12 questions, 7 questions including “scientists concern about others,” “scientists respect others’ opinion,” “scientists are funny,” “scientists have a sense of art,” “scientists respect human-beings,” “scientists have a sense of responsibility,” and “scientists have religion,” appeared statistically significant, and thus self-directed scientific research activities changed schoolers’ perception about scientists positively. Second, male schoolers had positive perception about scientists for 11 and all of 12 questions in a pre-test and a post-test, respectively. Among total 12 questions, 5 questions, including “scientists concern about others,” “scientists respect others’ opinion,” “scientists are funny,” “scientists have a sense of art,” and “scientists have a sense of responsibility” appeared statistically significant, and thus self-directed scientific research activities changed schoolers’ perception about scientists positively. Third, female schoolers had positive perception about scientists for 11 and all of 12 questions in a pre-test and a post-test, respectively. Among total 12 questions, 2 questions including “scientists are funny” and “scientists respect human-beings” appeared statistically significant, and thus self-directed scientific research activities changed male schoolers’ perception about scientists more than that of female schoolers. In the result of a DAST-C test, first, middle schoolers’s degrees of fixed image about scientists showed a statistically significant difference. Self-directed scientific research activities were found to effectively decrease schoolers’s degrees of fixed image about scientists. Second, the division of male and female middle schoolers resulted in a statistical significance in those both parties. Hence, self-directed scientific research activities were found to have a positive effect on changing male and female middle schoolers’ image about scientists. Third, gender’s effect on the change of image about scientists showed no significant difference between male and female schoolers in a pre-test, but a significant difference in a post-test; so, self-directed scientific research activities gave more effect on female schoolers’ image change about scientists than on the counterpart of male schoolers. In conclusion, self-directed scientific research activities had a positive effect on schoolers’ change in meta-cognition, especially on monitoring and control abilities among its sub-factors. Also, self-directed scientific research activities had some effects on schoolers’ perceptual change in the nature of science, especially great effects on perception about scientists. Therefore, scientific research academies and creative science camps as self-directed scientific research activities are needed to launch, and it is especially very useful to employ them into school science clubs.

과학 교육에 활용할 수 있는 인포그래픽 학습 자료의 개발 및 적용

문양희 제주대학교 대학원 2015 국내박사

The objective of this study is to develop the infographics learning materials for the science education of elementary school, and then to examine the influence of the class applied with the developed materials on elementary school students' scholastic achievement and interest in science. In order to examine the differences in the scholastic achievement and interest in science between two groups, the independent samples t-test was conducted. To examine the changes within groups, the paired samples t-test was conducted. To understand students' opinions about science class using infographics, the survey was performed for students of the experimental group. The results were analyzed by calculating the frequency and percentage of each response to each question. The results of this study are like following. First, the infographics learning materials for science class of Grade 5 were developed based on the analysis of the contents of science textbook revised in 2009 and a guide for teachers. The infographics learning materials for the unit「1. Temperature and Heat」for the first semester of Grade 5 were produced in the form of motion infographics and image infographics. Second, the science class using the infographics learning materials showed significant effect on the improvement of elementary school students' scholastic achievement compared to general science class. In other words, the science class using the infographics learning materials has positive influence on the improvement of scholastic achievement, and it is more effective on female students than male students. Third, the science class using the infographics learning materials has influence on the changes of students' interest in science. The students receiving the science class using infographics showed increased interest in science while students receiving general science class showed lowered interest in science. It means that the infographics learning materials had influence on learners' interest in science. However, there were no statistically significant differences. In the results of analyzing the results of the post-test between the experimental and control groups regarding the interest in the extramural science area, there were significant differences between two groups. The test results of interest in science in accordance with sex did not show significant differences. Fourth, most of the students receiving the science class using the infographics learning materials developed by this study gave positive responses that it was more interesting than general class and they were able to understand the contents more easily. They also had positive opinions about developing/using the infographics learning materials for other units and other subjects on top of the infographics learning materials used by this study. Such results show that it would be necessary to continuously develop the infographics learning materials for other units and other areas. Also it would be necessary to have future researches on if the infographics learning materials have influence on students by working as general multimedia leaning materials, or if the infographics learning materials have bigger influence than other multimedia learning materials.

科學的 探究活動과 멘토제 및 科學敎授方法에 대한 初·中學校 學生, 敎師의 認識

김창건 제주대학교 대학원 2015 국내박사

The purpose of this study is to survey the scientific inquiry activities in the elementary and middle school(Student-led Inquiry Activity), the awareness of the teachers’ participation as a mentor, and the preference for science teaching and learning method, and then to compare them from the perspective of a teacher and a student each. After that, to check the possible problems and to find out the solution for the improvement is the ultimate objective of this study. In terms of the elementary and middle school students, first of all, to get the ideas about the small group scientific inquiry activities, some questionnaire items developed by Jeong et al.(2006) were revised and used. Secondly, to survey the awareness of the teachers’ participations as a mentor, A 10-item questionnaire was made after. According to the result of the reliability test, Cronbach’s Alpha coefficient for the questionnaire is 0.84. Finally, to understand the preference for science teaching and learning method, the questionnaire developed by Jones & Harty(1978) was revised and used. This is to survey which method the students prefer, a traditional teaching method or a student-led inquiry learning method. According to the survey, the scientific inquiry activities are done more in the lower grades and for each task it takes about 4 hours. It is less than 6 hours suggested in 2007 Revised Curriculum. Also, among many kinds of activities most activities are the textbook-based inquiry activities, so students-led inquiry activities taking more time are needed. When students perform the students-led inquiry activities, they think to set a subject and to assign a role in a team are the most difficult ones. In spite of these difficulties, they understand the subject better. Like this, more opportunities should be provided to think scientifically by themselves. For the roles of a mentor teacher, students expect the positive influences like getting helpful advice. For the teaching and learning method, students prefer students-led inquiry learning method to the traditional teaching method. It points to the need of students-led inquiry activities. In terms of teachers, many teachers feel burden for the inquiry activities, so most of the cases can be done simply. This burden and the group organizing by teachers lead to students’ passive attitude. During the inquiry activities teachers focus on acquiring science precess skills, improving communicative skills, and understanding the fundamental concepts. Most teachers think that there’s a difficulty in collecting various materials for task performance. As a cognitive effect students memorize what they learn through the inquiry activities based on the problem solving and experiences. As a social and affective effect most students say that they can feel confident and successful. This result points to the need of designing and developing many kinds of activities up to each students’ group level. Also, there’re positive replies about the teachers’ participation as a mentor because students expect to get a new and different view and to feel confident by sharing ideas with teachers. This study can be helpful for designing and operating the scientific inquiry activities. Also, it can useful tips for developing science teachers’training program.

Fe₄₀Al₃₀Si₃₀기계적합금화 과정에서의 구조변화

윤지원 충북대학교 2014 국내석사

본 연구에서는 FeAlSi 합금을 각각 1, 2, 4, 6, 12, 25시간 동안 SPEX 8000 Mixer & Miller ball milling을 이용한 기계적 합금법으로 제조하였다. 합금화 과정에서 시료의 구조적 특성을 분석하였다. 구조적 특성은 XRD를 통해 시료의 결정구조 변화를 분석하였고, EXAFS를 통해 국소 구조변화를 분석하였다. 합금화는 1시간부터 2시간 사이에는 합금화가 전혀 진행되지 않다가 4시간이후부터 구조가 변화하여 합금화가 진행되어 12시간이후에는 합금화가 완료되었다는 것을 확인하였다. 본 연구를 통해 간단한 기계적 합금법으로 합금이 가능함을 알 수 있었다. In this study, FeAlSi alloys were made by the mechanical alloying technique. The FeAlSi alloys was prepared with periods of 1, 2, 4, 6, 12 and 25 hours by using SPEX 8000 Mixer & Miller ball milling. During mechanical alloying process, fine surface characteristic analysis and structural characteristic analysis were performed. The structural evolution of samples was examined by the X-ray diffraction(XRD) and the extended X-ray absorption fine structure(EXAFS). According to the experimental result, it was shown that the alloying process was activated after 4 hours milling. The powder of the samples was refined in 6 hours milling. Finally, the alloying process was finished almost after 12 hours milling. As the result, the alloy through a simple mechanical alloying was possible to know.

EXAFS 분석을 통한 금속원자들의 비조화열진동에 관한 연구

원미희 충북대학교 대학원 2004 국내석사

고온초전도 GdBCO 박막 선재의 물리적 특성

박병두 전북대학교 일반대학원 2018 국내석사

시판 중인 고온초전도 GdBCO CC(Coated Conductor) 박막선재 시편들을 PPMS(Physical Property Measurement System)를 이용한 4-단자 통전법(Four Probe Method, FPM) 및 마그네토미터(Magnetometer) 자화법 등을 통해 기본적인 전기적 및 자기적 초전도 특성들을 조사하였다. 통전 전류에 따른 저항 R의 온도 의존성 R(T)을 측정하여, 초전도 상변이가 일어나는 영역에서 저항 R의 10 %와 90 %에 해당하는 기준 값으로 비가역자기장 Hirr과 상부임계자기장 Hc2값들을 각각 구하였다. 임계전이온도 Tc 근처 영역에서 Hirr(T) 데이터들이 멱-법칙(power-low) 관계식 Hirr=Hirr(0)[1-T/Tc]^2에 매우 잘 일치하고, 인가하는 자기장의 방향이 CC 시편의 c-축에 평행한 경우와 ab-평면에 평행한 경우에 n 값은 각각 1.33과 1.51이다. Hirr(T)와 유사하게 Hc2(T) 데이터들도 Tc 근처 영역에서 BCS 형태 함수 관계식인 Hc2=Hc2(0)[1-(T/Tc)^α]^β에 잘 일치하며, 인가하는 자기장의 방향이 CC 시편의 c-축에 평행한 경우와 ab-평면에 평행한 경우에 α는 각각 0.37과 0.64이고, β는 각각 1.33과 1.17이다. 한편, 자기모멘트 m의 자기장 H의 의존성 m(H)을 측정하여 비가역자기모멘트 △mirr을 구하고, Bean 모델인 Jc∝△Mirr∝△mirr을 적용하여 GdBCO CC의 임계전류밀도 Jc와 자기장의 Jc∝H^(-δ) 관계식의 δ 값으로부터 자속거동 특성을 조사하였다. Tc 근처에서 인가하는 자기장이 GdBCO CC 시편의 ab-평면에 평행한 경우의 δ 값이 c-축에 평행할 때 보다 2배 이상 크지만, 온도가 감소할수록 δ 값들의 차이가 점차적으로 줄어들어 온도가 0 K일 때 δ ~ 0.25 정도로 서로 일치함이 예측되었다. 마지막으로 m(H) 데이터에서 △m~0 으로 시작되는 자기장을 Hirr으로, 높은 자기장 영역의 가역적인 m 데이터들이 선형적인 변화에서 벗어나는 순간의 자기장을 Hc2로 각각 구하였다. 그리고 임계전이온도 Tc 근처에서 Hirr(T) 데이터들이 멱-법칙 관계식 Hirr=Hirr(0)[1-T/Tc]^2에 적당히 일치함을 확인할 수 있었다. 인가하는 자기장의 방향이 CC 박막선재 시편의 c-축에 평행한 경우에 n=1.21 이다. 또한 Hirr(T)와 유사하게 Hc2(T) 데이터들이 Tc 근처 영역에서 BCS 형태 함수 관계식인 Hc2=Hc2(0)[1-(T/Tc)^α]^β에 잘 일치하며, 인가하는 자기장의 방향이 CC 시편의 c-축에 평행한 경우 α는 0.02이고, β는 0.71이다.

복합렌즈를 이용한 광포획된 나노입자의 수송거리 향상에 대한 연구

박영도 전북대학교 일반대학원 2018 국내석사

강하게 집속된 빛이 굴절률이 다른 매질로 입사하는 상황에서 굴절률 비매칭에 의한 구면수차가 발생하여 광포획된 입자를 빛의 진행방향으로 깊은 곳까지 수송하기 어렵다. 렌즈 사이의 거리를 조절해 수차를 조절할 수 있는 복합렌즈를 설계하여, 수송거리를 향상시켰다. OSLO(Optical Software for Layout and Optimization)를 이용하여 렌즈 6개로 구성된 복합렌즈 계를 직접 설계하였다. 이 복합렌즈는 계 내부 렌즈 위치를 독립적으로 조절하여 수차를 조절할 수 있다. 본 연구에서는 수차 보정에 영향이 큰 두 부분을 조절하였다. 광축방향으로 포획 깊이를 조정하며 포획된 입자의 운동을 BFPI(Back Focal Plane Interferometry)를 이용하여 측정하였으며, 각 깊이에서 수차를 보정하여 동일한 방식으로 운동을 측정하였다. 입자에 작용하는 힘을 계산하기 위해 입자의 크기에 따라 힘을 구하는 방법을 본 논문에 설명했다. 특히 힘을 구하는 방법 중 일반화 된 로렌츠-미 이론(Generalized Lorentz-Mie Theory)으로 힘을 계산해 본 실험의 결과와 비교하였다. 150 nm 입자의 경우 GLMT로 계산한 표면에서 포획 힘의 용수철 상수 값은 12.9 pN/µm이다. BFPI로 측정한 값은 12.2 pN/µm이다. 2 mm 위치에서는 4.81 pN/µm정도로 감소하지만, 렌즈간 거리를 조정하여 8.26 pN/µm까지 복구했다.

Fe60Co40 기계적합금의 구조 및 자기적 특성에 관한 연구

김석호 충북대학교 2009 국내석사

본 연구에서는 기계적인 합금으로의 철과 코발트의 분말 합금의 가능 여부와 합금이 이루어지면서 구조적이나 자기적인 특성 변화를 알아보기 위해 SPEX 8000 Miller를 사용하여 비교적 간단한 합금 공정인 기계적 합금화에 의한 Fe와 Co의 합금 분말을 제조 하였으며, milling 시간을 변화시키면서 VSM을 이용한 자기적 특성과 XRD를 이용한 구조적 특성을 분석하였다. 본 연구에 사용된 시료는 Fe : Co 의 원자량비 60:40의 시료이며, 측정 실험은 XRD를 이용하여 격자상수의 변화와 결정립의 크기변화, 결정구조를 분석하였고, VSM을 이용하여 자화값의 변화와 보자력의 변화를 분석하는 실험을 시행하였다. 확인 결과 Fe60Co40 합금분말은 milling time 4시간 이후부터 본격적인 합금이 진행되기 시작하였고, 24시간에 이르기 까지 합금이 진행됨을 알 수 있었다. 합금이 진행되면서 Co의 조밀육방격자(hcp)구조가 사라지면서 Co원자가 Fe의 체심입방격자(bcc)구조의 철 원자를 치환함을 알 수 있었다. 또한 비교적 자화값이 높은 Co의 관여도가 커져서 합금분말의 전체적인 자화가 시간이 지날수록 상승하는 것을 확인하였으며, 이러한 자화값의 변화는 합금의 구조변화와 연관성이 있음을 알 수 있었다. 본 연구를 통하여 Fe와 Co의 합금이 간단한 기계적 합금화를 통해서도 쉽게 얻을 수 있다는 것을 알 수 있었고, 높은 자기 밀도를 가지며 135 Oe 보자력을 갖는 자성 재료로서의 Fe-Co합금의 가능성을 제시해 줄 수 있었다. In this study, we manufactured Fe60Co40 alloy powders by mechanical alloying method with SPEX 8000 Mixer/Mill. We analyzed structural properties with the X-Ray diffractometer (XRD) and magnetic properties with the vibrating sample magnetometer (VSM). It was found that there is a relationship between the structure and magnetic properties of Fe60Co40 mechanical alloys in this study. By X-ray diffraction analysis, it was shown that the alloy began to grow after 4 hour milling and completed in 24 hour milling. In the alloying process, the characteristic peak of hcp shells of Co decreased continuously as the milling was progressed, and disappeared completely after 4 hours. The saturation magnetization of the alloys increased as milling time increased. This indicates that the Co atoms replace Fe atoms as the amount of Fe-Co alloy increased during the alloying periods.

J-PARC KOTO 실험을 위한 Downstream Charged Veto 검출기 제작 및 성능평가

김홍민 전북대학교 일반대학원 2020 국내석사

The Downstream Charged Veto (DCV) detector was fabricated and installed to suppress background events caused by the KLtopi+pi-pi0 decay for the KOTO experiment at J-PARC. The KOTO experiment aims to study the KLtopi0nunubar decay, of which branching ratio is expected to be 3*10^(-11) in the Standard Model [1]. At the single event sensitivity of 1.30*10^(-9) achieved with data taken in 2015, the number of KLtopi+pi-pi0 background events was estimated to be 0.05 [2]. Based on the Monte Carlo simulation, the KLtopi+pi-pi0 background events are remained due to undetected charged pions passing through the beam hole of electromagnetic calorimeter. They were not detected because of interaction with non-active materials such as Al pipe, G10-pipe and membrane. In order to detect the charged pions before they interact with those non-active materials, the DCV is placed in the most inner place of the KOTO detector system surrounding beam, where is highly evacuated down to 10^(-5) Pa. The DCV is composed of two plastic-scintillator pipes read out by Multi-Pixel Photon Counters (MPPC) through wavelength shifting fibers. In order to install the detector in very limited space, the MPPC is directly attached to the surface of the plastic scintillator. The light yield was 60 photoelectrons for 0.8 MeV energy deposit at the center of the DCV. After its installation, energy calibration was performed using cosmic-rays identified by detectors surrounding the DCV.