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        검색결과 57

        41.
        2003.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        There are terrestrial signatures of the solar activity cycle in ice core data (Ram & Stoltz 1999), but the variations in the sun's irradiance over the cycle seem too small to account for the signature (Lean 1997; Goode & Dziembowski 2003). Thus, one would expect that the signature must arise from an indirect effect(s) of solar activity. Such an indirect effect would be expected to manifest itself in the earth's reflectance. Further, the earth's climate depends directly on the albedo. Continuous observations of the earthshine have been carried out from Big Bear Solar Observatory since December 1998, with some more sporadic measurements made during the years 1994 and 1995. We have determined the annual albedos both from our observations and from simulations utilizing the Earth Radiation Budget Experiment (ERBE) scene model and various datasets for the cloud cover, as well as snow and ice cover. With these, we look for inter-annual and longer-term changes in the earth's total reflectance, or Bond albedo. We find that both our observations and simulations indicate that the albedo was significantly higher during 1994-1995 (activity minimum) than for the more recent period covering 1999-2001 (activity maximum). However, the sizes of the changes seem somewhat discrepant. Possible indirect solar influences on the earth's Bond albedo are discussed to emphasize that our earthshine data are already sufficiently precise to detect, if they occur, any meaningful changes in the earth's reflectance. Still greater precision will occur as we expand our single site observations to a global network.
        4,000원
        42.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 중학교 1학년 과학의 '지각의 물질과 변화' 단원을 공부한 중학생들이 학습한 지질개념을 자연환경과 생활주변에 얼마나 연계시켜 인식하고 있는가를 조사하여 학교교육과 생활환경과의 연계성을 논의하고 주변 자연환경의 차이가 개념 이해와 과학적 태도에 얼마나 영향을 주는지 연구하였다. 연구 대상은 전라북도 전주시, 부안군, 진안군 소재 중학교 2학년 학생 330명을 대상으로 조사했다. 광물과 암석의 경우, 학교학습에서 그 표본관찰 등으로 개념은 정립되어 있는 것으로 분석되었으나, 생활주변의 암석을 관심있게 관찰한 학생은 16%에 불과하며 대부분은 관심이 없다. 전라북도 내 소읍지역 부안과 진안지역에는 주변에 특별한 지층과 지질구조를 가진 채석강과 마이산 등이 있어 암석 및 지질구조의 야외관찰 학습에 연계 지도가 용이한 지역이나 전주지역 학생보다 관찰경험이 조금 많을 뿐, 전 지역 학생들 모두 야외관찰 학습을 거의 하지 않고 있다. '지각의 물질과 변화' 단원의 학습 시, 주변의 야외 관찰 학습장을 찾아서 광물과 암석을 채집해 관찰하고 크고 작은 지질구조를 입체적으로 관찰함으로써 학습의 효과를 높이도록 해야 한다.
        4,000원
        43.
        2002.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구에서는 최근 수행된 국제 비교 연구인 TIMSS-R과 PISA 2000에 나타난 우리 나라 학생들의 지구 과학영역에 대한 전체적인 성취도 및 성 차이 경향을 파악하였다. 이를 위해 1999년에 실시된 TIMSS-R에 포함된 33개의 지구 과학 관련 문항과 2000년에 실시된 PISA에 포함된 13개의 지구 환경 과학 문항에 대한 국제 및 국내 평균 정답율을 비교하였다. 분석 결과, 우리 나라 학생들은 문항 유형별로는 선택형 문항에서, 수행 영역별로는 단순 정보 이해문항에서 국제 평균 정답율에 비해 큰 차이를 보이며 높게 나타났다. 또한, 우리 나라 학생들은 그래프 해석, 표 해석등 자료 해석과 관련된 문항에서 국제 평균보다 특히 높은 정답율을 나타냈는데, 이러한 경향은 남학생들에게 더 두드러졌다. 한편, 우리 나라 학생들은 천문학 문항에서 상대적으로 가장 낮은 점수를 나타냈으며, 이는 특히 여학생에게 더 심하게 나타났다. 우리 나라 여학생들은 문항의 내용, 유형, 수행 영역 등 모든 부분에서 남학생들보다 낮은 정답율을 보여 심각한 성 차이를 드러냈다.
        4,600원
        44.
        2001.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The response of the earth's magnetosphere to the variation of the solar wind parameters and Interplanetary magnetic field (IMF) has been stud}ed by using a high-resolution, three-dimension magnetohydrodynamic (MHD) simulation when the WIND data of velocity Vx, plasma density, dynamic pressure, By and Bz every 1 minute were used as input. Large electrojet and magnetic storm which occurred on October 21 and 22 are reproduced in the simulation (fig. 1). We have studied the energy transfer and tail reconnect ion in association with geomagnetic storms.
        3,000원
        45.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        The Chinese ancient accounts of timing observations of 48 lunar eclipses and the secular variation of the Earth's spin speed are discussed. A series of ΔT expressing the secular deceleration of the Earth's rotation was obtained. The average increase rate of length of the day is about 1.5 milliseconds per century.
        46.
        1991.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyse the type of student's misconceptions on earth science concepts and its sources in grades 7 to 9. The test questionnaire was develpoed to investigate their misconceptions to the selected students. The following conclusions were drawn. 1) The sellected students had the various types of misconceptions on earth science concepts. 2) There were no grade differences in the patterns of the misconceptions. 3) The sources of student's misconceptions were resulted from the poor development of cognitive structures, the influences of environments, the error of information processing. 4) The misconceptions were not changed and corrected easily.
        5,400원
        47.
        1990.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of fundamental bases for the desirable Science Education is effective evaluation, and the objectives of the Science Education can be used for the reasonable basis of this evaluation. In this paper, to study the current state of the high school Earth Science Education, comparison was made between the objectives of Education proposed by textbook and those to be measured by Scholastic Achievement test, and the result was analyzed. 1. The objectives of both the textbook and Scolastic Achievement test are highly oriented to obtain theory and comprehension. 2. The objectives which measure the Process of Scientific Inquiry are to some extent satisfied by the textbook but not by the Scholastic Achievement test. Consequently the future evaluation process should be modified in order to evaluate properly the ability for the process of Scientific Inquiry of the students properly.
        4,300원
        48.
        1989.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. The aim of this study is to find the theoretical foundation of science education and to offer a basic materials and efficient suggestions for the 2000s Earth Science by analyzing and comparing the new curriculum amended in 1988 and the old one amended in 1981. 2. The main contents of this study is to find the problems in curriculum and to suggest the way to improve the curriculum by analyzing and comparing the new and old curriculum. 3. The problems that may appear in the new curriculum are as follows. (1) It's hard to expect the normal Earth Science Education in high school because Earth Science is designated as an optional subject in natural course. (2) It is contradictory to relation in learning to unify the Earth Science I and Biology I into Science I in new curriculum. (3) If the new curriculum goes in effect it is natural that Earth Science teachers quality should be lowered because able students will avoid entering the Department of Earth Science Education in university. 4. The suggestions to help improve the Earth Science curriculum in 2000s are as follows. (1) For the normal Earth Science Education, Earth Science should be designated as a required subject in civic science course as well as in natural course in high school. (2) The aim of Earth Science Education should be amended not to be dicipline centered curriculum but to satisfy the future society or individual's desire (3) The intergrated science should be researched profoundly and it is necessary to name Earth Science Geophysics, which is unified with physics. (4) Natural science curriculum should be amended by the committee constituted with the specialist in science education, scientists, and science teachers ; it is not proper that science curriculum be reached and discussed by an reorganization in which a few specialists in science education join.
        4,000원
        49.
        1988.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to provide useful advices and basic data for the future Earth Science Education by analyzing the High School Earth Science textbooks. The analysis included 1) whether the contents of the textbook are properly selected suiting with Piaget's Intellectual development stage 2) whether the basic concept and successive concept are properly selected and organized. This study arrived at the following conclusions. 1) The greater part of highschool students are not able to think the formal operation when they are in need of thinking power in formal operation in the study of 48.696 of curriculum. 2) The contents of Earth Science textbook should be developed naturally from the concrete operation stage to the formal operation stage, but the methods of approaching curriculum are scattered through out the textbook. 3) There are many lessons that can't be practiced in laboratory. The textbook should be developed naturally from the simple structures to the complicated ones. Also it is necessary for teachers to conceive those problems and to be able to help the students approach the curriculum easily.
        4,000원
        50.
        2019.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The Earth’s outer radiation belt has long received considerable attention mainly because the MeV electron flux in the belt varies often dramatically and at various time scales. It is now widely accepted that the wave-particle interaction is one of the major mechanisms responsible for such flux variations. The wave-particle interaction can accelerate electrons to MeV energies, explaining the observed flux increase events, and can also scatter the electrons’ motion into the loss cone, resulting in atmospheric precipitation and thus contributing to flux dropouts. In this paper, we provide a review of the current state of research on relativistic electron scattering and precipitation due to the interaction with electromagnetic ion cyclotron (EMIC) waves in the inner magnetosphere. The review is intended to cover progress made over the last ~15 years in the theory and simulations of various issues, including quasilinear resonance diffusion, nonlinear interactions, nonresonant interactions, effects of finite normal angle on pitch angle scattering, effects due to rising tone emission, and ways to scatter near-equatorial pitch angle electrons. The review concludes with suggestions of a few promising topics for future research.
        51.
        2016.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The atmosphere strongly affects the Earth’s spin rotation in wide range of timescale from daily to annual. Its dominant role in the seasonal perturbations of both the pole position and spinning rate of the Earth is once again confirmed by a comparison of two recent data sets; i) the Earth orientation parameter and ii) the global atmospheric state. The atmospheric semi-diurnal tide has been known to be a source of the Earth’s spin acceleration, and its magnitude is re-estimated by using an enhanced formulation and an up-dated empirical atmospheric S2 tide model. During the last twenty years, an unusual eastward drift of the Earth’s pole has been observed. The change in the Earth’s inertia tensor due to glacier mass redistribution is directly assessed, and the recent eastward movement of the pole is ascribed to this change. Furthermore, the associated changes in the length of day and UT1 are estimated.
        52.
        2015.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Earth’s magnetopause separating the fast and often turbulent magnetosheath and the relatively stagnant magnetosphere provides various forms of free energy that generate low-frequency surface waves. The source mechanism of this energy includes current-driven kinetic physical processes such as magnetic reconnection on the dayside magnetopause and flux transfer events drifting along the magnetopause, and velocity shear-driven (Kelvin-Helmholtz instability) or density/ pressure gradient-driven (Rayleigh-Taylor instability) magnetohydro-dynamics (MHD) instabilities. The solar wind external perturbations (impulsive transient pressure pulses or quasi-periodic dynamic pressure variations) act as seed fluctuations for the magnetopause waves and trigger ULF pulsations inside the magnetosphere via global modes or mode conversion at the magnetopause. The magnetopause waves thus play an important role in the solar wind-magnetosphere coupling, which is the key to space weather. This paper presents recent findings regarding the generation of surface waves (e.g., Kelvin- Helmholtz waves) at the Earth’s magnetopause and analytic and observational studies accountable for the linking of the magnetopause waves and inner magnetospheric ULF pulsations, and the impacts of magnetopause waves on the dynamics of the magnetopause and on the inner magnetosphere.
        53.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        비정질 실리카겔은 Si와 O로 이루어진 가장 간단한 화합물로서, 표면에 다양한 구조의 물과 수산기, 그리고 합성과정에서 형성된 유기 리간드(ligand)를 함유하고 있어, 지권, 수권, 그리고 생물권의 상호작용을 이해하는 모델 시스템으로서 의미를 갖는다. 본 연구에서는 17O NMR 분광분석을 통해 비정질 실리카겔의 Si-O-Si와 Si-OH 산소 원자환경의 차이를 규명하고자 하였다. 이를 위해 SiCl4의 수화반응을 통해 17O이 집적된 비정질 실리카겔을 합성하였다. 1H과 29Si NMR 분광분석 결과, 비정질 실리카겔 표면에는 다양한 수소결합 세기를 가진 물과 수산기 이외에, Si-O·sR 형태의 유기 리간드가 존재함을 확인하였다. 이와 같은 유기 리간드는 에탄올 또는 증류수를 이용해 비정질 실리카겔을 초음파 세척함으로써 상당부분 제거 가능하다. 17O NMR 분광분석 결과, 짧은 펄스 길이(0.175μs)를 이용한 17O NMR 스펙트럼에서 Si-O-Si와 Si-OH 산소원자 환경이 거의 구분되지 않고 나타나는 반면, 특정 실험조건(2μs 펄스길이)의 17O NMR 스펙트럼에서는 약 0 ppm에서 빠른 동역학적 특성을 가지는 Si-OH로 추정되는 피크가 관찰되었다. 이 피크는 비정질 실리카겔 표면의 유기 리간드가 제거됨에 따라 더 뚜렷하게 관찰되며, 이는 유기 리간드와 비정질 실리카의 산소원자 사이의 상호작용이 존재함을 지시한다. 이와 같은 상호작용은 비정질 실리카겔 표면의 수산기의 원자구조에 대한 정보를 제공하며, 이를 통해 규산염 지구물질의 탈수반응 기작에 대한 이해를 고양시킬 수 있다. 따라서 궁극적으로 지구물질의 탈수반응에 기인하여 일어나는 섭입대의 중간깊이(약 70~300 km)에서 일어나는 지진의 미시적인 원인에 대한 실마리를 제시할 것으로 기대된다.
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