• Korean Journal of Optics and Photonics
• /
• v.14 no.5
• /
• pp.483-490
• /
• 2003

We have analyzed theoretically optical pulse propagation in a coherent atomic medium for amplification without inversion (AWI), which is achieved by adding incoherent optical pumping to a typical EIT system. In order to explain experimental results [Kim et al., J. Phys. B, 36, 2671(2003)] to control the group velocity of the optical pulse by changing pumping power, we established a 5-level atomic system and applied density matrix equations. This AWI model system is different from previous AWI systems from the viewpoint of using two levels for incoherent optical pumping isolated optically from the EIT (electromagentically induced transparency) system so that more atoms can participate in pulse speed control. We have found that population transfer by collisions between ground states plays a decisive role for efficient AWI, and more atoms are effective for slowing the pulse. Our numerical results are in good agreement qualitatively with experimental results.

• Journal of the Korean Magnetics Society
• /
• v.19 no.2
• /
• pp.74-79
• /
• 2009

We have investigated the magnetic education in elementary science of Korea. Text books and other related materials are analysed. Students learn playing with magnets in third grade and learn making electromagnets in sixth grade. Arrangement of topics are in accord with the historical development of electromagnetism in physics although the order is not well suited to other field of science. Teacher's guide books need to be developed to consider various environments in school such as city and country, and rich and poor town. Several details in the science textbook are pointed out for better education. Overall course looks sound.

• Journal of The Korean Association For Science Education
• /
• v.27 no.6
• /
• pp.497-509
• /
• 2007

Among many remedial approaches against the increasing unfavorableness toward school science, one of the prevalent findings studied by affective experts is that students' achievement in science and their attitude toward it has a relatively weak relationship. In contrast, cognitive experts assert that the conceptual change involves more than cognitive aspects, and may be influenced by affective factors such as beliefs, motivation, learning attitudes, and sociocultural contexts. The latter regards continuous conceptual change as leading to better student understanding of science with variables of students' attitude toward science. As an initial step toward illuminating the affective-cognitive learning aspects of science, the purpose of this study is to develop an instrument for analyzing the relationship between students' conceptual understanding and affective factors. Cognitive questionnaires from the database of distribution in students' misconceptions of physics (DMP project), and affective questionnaires from the Relevance of Science Education (ROSE project) are integrated into our instrument. The respondents are high school students in Okayama prefecture, Japan. Through the pilot test, the authors integrated attitude toward science (AS) and interest inventory (II) from ROSE into cognitive understanding (CD) from DMP. Statistical methodologies such as factor analysis and item total correlation theoretically discerned the effective sixty-three items from the two original item pools. Having discussed two validity issues, the authors suggest ongoing research associated with our affective-cognitive research perspective.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.02a
• /
• pp.135-135
• /
• 1999

• Proceedings of the Korean Magnestics Society Conference
• /
• 2008.12a
• /
• pp.280.1-280.1
• /
• 2008

• Communications of Mathematical Education
• /
• v.27 no.4
• /
• pp.487-498
• /
• 2013

Sang-Seol Lee(1870-1917) wrote a manuscript BaekSeungHoCho(百勝胡艸) in the late 19th century. BaekSeungHoCho was transcribed in classical Chinese from the 1879 Japanese book Physics(物理學) by Teizo Ihimori (1851-1916). Sang-Seol Lee, a famous independence activist, is also called Father of the Modern Mathematics Education of Korea, because of his early contribution to the modern mathematics education in the 19th century. In this paper, we introduce contents of his manuscript BaekSeungHoCho for the first time and discuss the significance of this book. Also, we show his contribution on the introduction to modern physics in the late 19th century Korea.

• Journal of Sensor Science and Technology
• /
• v.1 no.1
• /
• pp.53-57
• /
• 1992

We report the crystal growth and the electro-optic characteristics of $CdS_{1-x}Se_{x}$ thin films. $CdS_{1-x}Se_{x}$ thin films wire deposited on the alumina plate by electron beam evaporation technique in pressure of $1.5{\times}10^{-7}$ torr, voltage of 4kV, current of 2.5mA and substrate temperature of $300^{\circ}C$. The deposited $CdS_{1-x}Se_{x}$ thin films were proved to be a polycrystal with hexagonal structure through X-ray diffraction patterns. $CdS_{1-x}Se_{x}$ photoconductive films showed high photoconductivity after annealing at $550^{\circ}C$ for 30 minutes. And the films have been investigated the Hall effect, photocurrent spectra, sensitivity, maximum allowable power dissipation and response time.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2009.08a
• /
• pp.177-177
• /
• 2009

• Proceedings of the Korean Vacuum Society Conference
• /
• 2009.08a
• /
• pp.176-176
• /
• 2009

• Proceedings of the Korean Magnestics Society Conference
• /
• 2005.06a
• /
• pp.94-95
• /
• 2005