• 제목/요약/키워드: General physics

검색결과 491건 처리시간 0.022초

Causality between climatic and soil factors on Italian ryegrass yield in paddy field via climate and soil big data

  • Kim, Moonju;Peng, Jing-Lun;Sung, Kyungil
    • Journal of Animal Science and Technology
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    • 제61권6호
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    • pp.324-332
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    • 2019
  • This study aimed to identify the causality between climatic and soil variables affecting the yield of Italian ryegrass (Lolium multiflorum Lam., IRG) in the paddy field by constructing the pathways via structure equation model. The IRG data (n = 133) was collected from the National Agricultural Cooperative Federation (1992-2013). The climatic variables were accumulated temperature, growing days and precipitation amount from the weather information system of Korea Meteorological Administration, and soil variables were effective soil depth, slope, gravel content and drainage class as soil physical properties from the soil information system of Rural Development Administration. In general, IRG cultivation by the rice-rotation system in paddy field is important and unique in East Asia because it contributes to the increase of income by cultivating IRG during agricultural off-season. As a result, the seasonal effects of accumulated temperature and growing days of autumn and next spring were evident, furthermore, autumnal temperature and spring precipitation indirectly influenced yield through spring temperature. The effect of autumnal temperature, spring temperature, spring precipitation and soil physics factors were 0.62, 0.36, 0.23, and 0.16 in order (p < 0.05). Even though the relationship between soil physical and precipitation was not significant, it does not mean there was no association. Because the soil physical variables were categorical, their effects were weakly reflected even with scale adjustment by jitter transformation. We expected that this study could contribute to increasing IRG yield by presenting the causality of climatic and soil factors and could be extended to various factors.

연구데이터 레포지터리의 데이터 접근 및 이용 통제 정책 요소에 관한 연구 (A Study on Policy Components of Data Access and Use Controls in Research Data Repositories)

  • 김지현
    • 한국도서관정보학회지
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    • 제47권3호
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    • pp.213-239
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    • 2016
  • 전 세계적으로 오픈 데이터가 강조되는 환경에서 데이터의 공유 및 재이용으로 인해 발생하는 문제점을 최소화하기 위한 정책적 논의도 함께 진행되고 있다. 본 연구에서는 연구데이터 레포지터리에서 데이터의 접근 및 이용을 통제하는 정책요소들을 조사하고 학문 분야별로 그러한 정책 요소들의 공통점과 차이점을 살펴보는 것을 목적으로 하였다. 이를 위해 해외 연구데이터 레포지터리 37곳을 대상으로 데이터 접근 및 이용 통제를 규정하고 있는 정책 요소를 분석하였다. 생명과학 및 보건과학분야 20개 레포지터리, 화학 지구환경과학 물리학 분야 10개 레포지터리, 사회과학 및 일반과학 분야 7개 레포지터리로 구분하여 분석을 실시한 결과 저작권 및 라이선스 규정, 데이터 인용, 면책조항 및 엠바고 적용 관련 규정이 공통적으로 제시되는 정책 요소인 것으로 나타났다. 그러나 분야별로 규정되고 있는 정책 요소의 다양성에는 차이가 있는 것으로 나타났으며 이는 분야별로 강조되는 데이터 접근 및 이용 통제 근거의 차이를 반영하는 것으로 볼 수 있다.

물리치료학 교육의 변화에 부응하는 문제중심학습방법(Problem Based Learning) (Implementing PBL in Physical Therapy Education)

  • 황현숙;이우숙;임종수
    • 대한물리치료과학회지
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    • 제9권3호
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    • pp.179-186
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    • 2002
  • This study addresses the need to adopt teaching-learning approaches in physical therapy education that develop links between theory and clinical practice in a meaningful way. Problem-based learning (PBL) is presented as a useful way to educate physical therapy for the future. The essential characteristics of problem-based learning include: curricular organization around problems rather than disciplines; an integrated curriculum rather than one separated into clinical and theoretical components; and an inherent emphasis on cognitive skills as well as on knowledge. PBL as implemented in the health sciences, is an educational method in which the focus of learning is a small-group tutorial in which students work through health care scenarios. The goals of the health care scenarios are to provide a context for learning, to activate prior knowledge, to motivate students, and to stimulate discussion. Learning is student-centered rather than faculty-centered, and self-directed learning is emphasized. Whereas the former focuses on critical thinking and clinical judgement, the latter's emphasis is on clinical competency. The physical therapist (PT) program at Cheju Halla college is a partial integrated problem-based curriculum. The history and process of PBL in general and in the PT program are reviewed. Long-term advocates of PBL stress that it is the only known method for preparing future professionals to be able to adapt to change, learning how to reason critically, enabling a holistic approach to health.

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대칭형과 비대칭형 복사기 줌 렌즈계의 광학적 성능 비교 분석 (The optical capacity's comparison, analysis of copier zoom lens system between symmetric and asymmetric forms)

  • 지택상;임현선;김봉환
    • 한국안광학회지
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    • 제6권2호
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    • pp.1-9
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    • 2001
  • 본 논문에서는 기존에 설계된 복사기 줌 렌즈계를 선택하여 광학적 성능을 계산하여 분석하여 보았다. 이 렌즈계는 유한 물점에 대한 zoom 렌즈계로서 우리가 일반적으로 사용하는 무한 물점에 대한 카메라 zoom 렌즈와는 달리, 고정된 물체와 상면사이에서 움직이기 때문에 제한된 이동영역을 갖게 된다. 대칭형과 비대칭형의 두 복사기 렌즈계의 광학적 성능을 비교 분석한 결과, 비대칭형이 비교적 안정된 수차량을 이루고 있고, 수차보정을 위하여 많은 노력이 있었음을 알 수 있었다. 이것으로 미루어 보아 대칭형은 고정 초점 렌즈계에서는 대칭형의 특성상 자동으로 개선되는 수차들로 인하여 그 역할을 충분히 감당하고 있지만, 줌 렌즈계로 사용 시에는 대칭형을 유지하면서 그 성능을 개선시키는 데에는 한계가 있다고 볼 수 있다.

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Sources of the High-Latitude Thermospheric Neutral Mass Density Variations

  • Kwak, Young-Sil;Richmond, Arthur;Deng, Yue;Ahn, Byung-Ho;Cho, Kyung-Suk
    • Journal of Astronomy and Space Sciences
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    • 제27권4호
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    • pp.329-335
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    • 2010
  • We investigate the sources of the variation of the high-latitude thermospheric neutral mass density depending on the interplanetary magnetic field (IMF) conditions. For this purpose, we have carried out the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) simulations for various IMF conditions under summer condition in the southern hemisphere. The NCAR-TIEGCM is combined with a new empirical model that provides a forcing to the thermosphere in high latitudes. The difference of the high-latitude thermospheric neutral mass density (subtraction of the values for zero IMF condition from the values for non-zero IMF conditions) shows a dependence on the IMF condition: For negative $B_y$ condition, there are significantly enhanced difference densities in the dusk sector and around midnight. Under the positive-$B_y$ condition, there is a decrease in the early morning hours including the dawn side poleward of $-70^{\circ}$. For negative $B_z$, the difference of the thermospheric densities shows a strong enhancement in the cusp region and around midnight, but decreases in the dawn sector. In the dusk sector, those values are relatively larger than those in the dawn sector. The density difference under positive-$B_z$ condition shows decreases generally. The density difference is more significant under negative-$B_z$ condition than under positive-$B_z$ condition. The dependence of the density difference on the IMF conditions in high latitudes, especially, in the dawn and dusk sectors can be explained by the effect of thermospheric winds that are associated with the ionospheric convection and vary following the direction of the IMF. In auroral and cusp regions, heating of thermosphere by ionospheric currents and/or auroral particle precipitation can be also the source of the dependence of the density difference on the IMF conditions.

환경 교수학습법에 대한 과학과와 사회과 교사들의 인식 (Perceptions of Korean Science and Social Science Teachers Regarding Teachers/Learning Methods for Environmental Education)

  • 최경희
    • 한국환경교육학회지:환경교육
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    • 제14권2호
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    • pp.40-50
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    • 2001
  • To meet the objectives of environmental education, teachers especially have to perceive the importance of environmental education, comprehend various characteristics of teaching/learning methods, and be able to conduct classes by choosing proper teaching/leaming methods in accordance with a specific purpose and educational focus about environmental education. Therefore, it Bs necessary to investigate the current status of Korean environmental education and provide teachers with appropriate environmental teaching/leaming methods. To this end this study aims to examine Korean science teachers'perceptions'on environmental education and the kind of teaching/learning methods which can be utilized in environmental education. Teachers who completed the survey were 135 science teachers from middle and high schools in Seoul, and 126 social science teachers from Kyoungki province. The majors of the science teachers were in physics, chemistry, biology, geology, and earth science. Also, there was one teacher who majored in special education. For social science teachers two majors were common, geography and general sociology. After analysis of the data from the surveys the results are as follows. First, science and social science teachers in middle and high school recognized the necessity of environmental education in school education. Second, most teachers had applied environment related topics to their subject of study occasionally, but they mostly concurred that environment related contents should be included in their textbooks. Third, science teachers agreed that field trip, discussion, and the STS approach were the most proper methods for environmental education, and social science teachers agreed that field trips, inquiry, and discussion were the most appropriate methods for a teaching environment. They realized that they should decide good teaching-learning methods appropriate to the objectives and content needed for effective environmental education as they selected different teaching-learning methods according to detailed environmental objectives and contents in their textbooks.

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초등학교 학생들의 자기장 개념 분석과 인지양식의 차이에 따른 대안실험의 효과 (The Effect of an Alternative Experiment for the Formation of Student's Conceptions about the Magnetic Fields of a Permanent Magnet by Cognitive Styles)

  • 오광택;윤석주
    • 한국자기학회지
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    • 제26권5호
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    • pp.159-167
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    • 2016
  • 초등학교 6학년 과학교과 영구자석 주위의 자기장에 대한 학습에서 나타나는 학생들의 자기장 개념 유형을 조사하였다. 그리고 학생들의 영구자석 주위의 자기장에 대한 오개념 개선을 위한 나침반을 사용하는 대안실험을 제안하였으며 학생들의 인지양식에 따른 효과를 비교하였다. 영구자석 주위에 철가루를 뿌려 관찰한 자기장에 대해 부분 분포 모형, 극 분리 모형, 균질 분포 모형, 장 모형의 4가지 개념 모형이 나타났으며, 영구자석과 나침반을 이용하여 자기장을 관찰한 실험에서는 철가루 실험에서 나타났던 자기장 모형들이 연속, 변형, 복잡화되었는데 극 분리 모형, 복합 균질 분포 모형, 장 모형의 3가지 자기장 개념 모형으로 나타났다. 대안실험을 통해서 올바른 자기장 개념의 형성 비율이 장의존적인 학생들에게 유의미하게 높은 것으로 나타났다.

SPATIAL DISTRIBUTION OF STARS AROUND SIX METAL-POOR GLOBULAR CLUSTERS IN THE GALACTIC BULGE

  • Chang, Cho-Rhong;Kim, Jae-Woo;Matsunaga, Noriyuki;Han, Mihwa;Ko, Jongwan;Chun, Sang-Hyun;Kang, Minhee;Sohn, Young-Jong
    • 천문학회지
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    • 제46권6호
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    • pp.203-224
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    • 2013
  • Wide-field $JHK_s$ images obtained with the SIRIUS near-infrared camera of the IRSF 1.4m telescope are used to examine the tidal structures of the spatial stellar configuration around six metal-poor ([Fe/H]< -1.0) globular clusters located within 3 kpc from the Galactic center. The radial surface density profiles are obtained from the surface photometry of the cluster images and the star counting for the photometric data. For the star counting, candidates of cluster member stars are selected with an filtering algorithm in color-magnitude diagrams. We find that the six target clusters show tidal overdensity features in the radial surface density profiles. There is a break inside the tidal radius for each cluster, and the profile in the outer overdensity region is characterized by a power law. Two-dimensional density maps of all the clusters show distorted asymmetric stellar configurations in the outer region. In five out of the six target clusters, the overdensity features are likely to be associated with the effects of the Galaxy dynamical interaction and the cluster space motions. The observed tidal configurations of stars suggest that several metal-poor clusters in the Galactic bulge are possibly surviving remnants of mergers to build the old stellar system of the Galactic bulge.

Filled Skutterudites: from Single to Multiple Filling

  • Xi, Lili;Zhang, Wenqing;Chen, Lidong;Yang, Jihui
    • 한국세라믹학회지
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    • 제47권1호
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    • pp.54-60
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    • 2010
  • This paper shortly reviews our recent work on filled skutterudites, which are considered to be one of the most promising thermoelectric (TE) materials due to their excellent power factors and relatively low thermal conductivities. The filled skutterudite system also provides a platform for studying void filling physics/chemistry in compounds with intrinsic lattice voids. By using ab initio calculations and thermodynamic analysis, our group has made progresses in understanding the filling fraction limit (FFL) for single fillers in $CoSb_3$, and ultra-high FFLs in a few alkali-metal-filled $CoSb_3$ have been predicted and then been confirmed experimentally. FFLs in multiple-element-filled $CoSb_3$ are also investigated and anonymous filling behavior is found in a few specific systems. The calculated and measured FFLs, in both single and multiple-filled $CoSb_3$ systems, show good accordance so far. The thermal transport properties can be understood qualitatively by a phonon resonance scattering model, and it seems that a scaling rule may exist between the lattice thermal resistivity and the resonance frequency of filler atoms in filled system. Even though a few things become clear now, there are still many unsolved issues that call for further work.

한국 개화기 기독교학교 교과서의 서지학적 연구 (A Bibliographical Research on Textbooks of Missionary Schools in Korea during the Opening Period)

  • 김봉희
    • 한국문헌정보학회지
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    • 제23권
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    • pp.63-106
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    • 1992
  • The opening period of Korea was the period of modernisation amidst the conflicts between conservative and progressive sections with penetration of Western powers after 1876. With the opening modernisation accompanied modernisation of education. Missionary schools established by protestant missionaries played a crucial role in educational modernisation in the period of opening. In this article, the process of educational modernisation and the ways in which the ideas of democracy and equality were taught in the earliest schools, Paejae, Ewha, Kyoungsin and Chungsin are analysed through the method of bibliographical investigation of the textbooks used by these schools. No textbook prior to 1900 was found and in general there were no textbooks such as we know today. Usually English reading material and the Bible were the main teaching materials. Teachers kept their own copies of hand-written texts which were translated versions of American textbook. Since the same teacher taught in a number of schools, they shared same curriculum. In the early period, English Bible was taught so that English and the Bible lessons were not separated but gradually history and geography were added. Teaching of Hangul, and Korean history were added to encourage the sense of national identity and patriotism. In the case of Chungsin, for biology class, pupils were sent to Che-jung-won to learn human physiology, chemistry and physics, which shows an emphasis on science education. Vocational education was carried out; in the case of Paejae, a printing workshop was set up enabling students to earn some money at the same time as learning. Also in Kyungsin, skills of woodwork and basket weaving were stressed. Ewha also held a bazaar of the work made in sewing classes. Establishment of missionary schools brought about a great contribution in modernising Korean society and the Christian spiritual education of these schools lay the foundation for building democracy in Korea.

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