• Title/Summary/Keyword: energy space

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Review of Computational Methods for Space-time Reactor Kinetics

  • Chae, Sung-Ki
    • Nuclear Engineering and Technology
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    • v.11 no.3
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    • pp.219-229
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    • 1979
  • The current status of the computational methods and computer codes for the analysis of reactor kinetics is reviewed. Computational methods which have been developed for space-dependent transient analyses are presented and recent progress in the development of methods is discussed.

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SPACE WEATHER RESEARCH BASED ON GROUND GEOMAGNETIC DISTURBANCE DATA (지상지자기변화기록을 이용한 우주천기연구)

  • AHN BYUNG-HO
    • Publications of The Korean Astronomical Society
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    • v.15 no.spc2
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    • pp.1-13
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    • 2000
  • Through the coupling between the near-earth space environment and the polar ionosphere via geomagnetic field lines, the variations occurred in the magnetosphere are transferred to the polar region. According to recent studies, however, the polar ionosphere reacts not only passively to such variations, but also plays active roles in modifying the near-earth space environment. So the study of the polar ionosphere in terms of geomagnetic disturbance becomes one of the major elements in space weather research. Although it is an indirect method, ground magnetic disturbance data can be used in estimating the ionospheric current distribution. By employing a realistic ionospheric conductivity model, it is further possible to obtain the distributions of electric potential, field-aligned current, Joule heating rate and energy injection rate associated with precipitating auroral particles and their energy spectra in a global scale with a high time resolution. Considering that the ground magnetic disturbances are recorded simultaneously over the entire polar region wherever magnetic station is located, we are able to separate temporal disturbances from spatial ones. On the other hand, satellite measurements are indispensible in the space weather research, since they provide us with in situ measurements. Unfortunately it is not easy to separate temporal variations from spatial ones specifically measured by a single satellite. To demonstrate the usefulness of ground magnetic disturbance data in space weather research, various ionospheric quantities are calculated through the KRM method, one of the magneto gram inversion methods. In particular, we attempt to show how these quantities depend on the ionospheric conductivity model employed.

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SOLAR OBSERVATIONAL SYSTEM OF KYUNGHEE UNIVERSITY (경희대학교 태양관측시스템)

  • KIM IL-HOON;KIM KAP-SUNG
    • Publications of The Korean Astronomical Society
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    • v.13 no.1 s.14
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    • pp.39-54
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    • 1998
  • We have developed solar observational system in the department of Astronomy & Space Sciences of KyungHee University, in order to monitor solar activities and construct solar database for space weather forecasting at maximum of 23rd solar cycle, as well as an solar education and exercise for undergraduate students. Our solar observational system consists of the full disk monitoring system and the regional observation system for H a fine structure. Full disk monitoring system is made of an energy rejection filter, 16cm refractor, video CCD camera and monitor. Monitored data are recorded to VHS video tape and analog output of video CCD can be captured as digital images by the computer with video graphic card. Another system for regional observation of the sun is made of energy rejection filter, 21cm Schmidt-Cassegrain reflector, H a filter with 1.6A pass band width and $375\times242$ CCD camera. We can observe H a fine structure in active regions of solar disk and solar limb, by using this system. We have carried out intense solar observations for a test of our system. It is found that Quality of our H a image is as good as that of solar images provided by Space Environmental Center. In this paper, we introduce the basic characteristics of the KyungHee Solar Observation System and result of our solar observations. We hope that our data should be used for space weather forecasting with domestic data of RRL(Radio Research Laboratory) and SOFT(SOlar Flare Telescope).

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Development of Freeze-dried Miyeokguk, Korean Seaweed Soup, as a Space Food Sterilized by Irradiation (동결건조 미역국을 이용한 방사선 멸균 우주식품 개발)

  • Lee, Ju-Yeon;Song, Beom-Seok;Park, Jin-Gyu;Cho, Won-Jun;Kim, Jae-Hun;Yoon, Yo-han;Choi, Jong-il;Lee, Ju-Woon
    • Journal of Radiation Industry
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    • v.4 no.1
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    • pp.59-64
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    • 2010
  • This study was conducted to evaluate the microbial (Total aerobic count, Coliform, Coagulase positive Staphylococci, Salmonella, Yeast/Mold, Escherichia coli, Bacillus cereus), Hunter'color values ($L^*$, $a^*$, $b^*$) and organoleptic quality of freeze-dried Miyeokguk, Korean seaweed soup in space food. Bacillus cereus was 1 log level while not detected in the sample irradiated at 10 kGy. Hunter's color values of the samples irradiated less than 10 kGy was not significantly different (p>0.05). The sensory evaluation result showed that the preference scores in all the sensory properties decreased when it was irradiated over 10 kGy, but sensory score of less than 10 kGy samples was similar in all terms. Therefore, it was considered that gamma irradiation at 10 kGy was enough to sterilize the freeze-dried Miyeokguk without deterioration of sensory quality.

A Study on the Sustainable Characteristics of Sustainable Architectural Space viewed in the Eco-Aesthetic perspective - Focusing on korean traditional residential space - (생태 미학적 관점에서 본 지속가능한 건축 공간 특성에 관한 연구 - 한국 전통 주거 공간을 중심으로 -)

  • Yang, Eun-Ji;Kim, Kai-Chun
    • Korean Institute of Interior Design Journal
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    • v.21 no.4
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    • pp.31-39
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    • 2012
  • Ecosystem and environment have been a serious challenge facing the modern society. It's been the new paradigm from ecological view of the world and the alternative based on Orientalism. From the Oriental standpoint, ecological aesthetics and sustainable architecture are no longer new, which then servers the background of this study. The nature and the space, the life where the human is harmonized and integrated and the wish to make the balance through that life are the basic philosophy which the Orientalism has pursued. Based on such a basic concept, the study is intended to review the connectivity, expression approach and the features in Korean traditional residential space based on previous studies on ecological aesthetics and sustainable architecture. Such attempt is meaningful in seeking the possibility of presenting the new frame as well as forming the various views to the traditional space and spatial recognition. The nature was categorized into tangible element and intangible element and also direct approach and indirect approach before evaluating the characteristics. Sustainable architecture is not the concept to simply maintain or sustain the environment, but plays more important role in economical aspect. Traditional space accommodates the nature and circulation principle and the circulation in the nature controls the energy and enhances the efficiency, playing significant role. The nature itself serves the alternative energy and has the aesthetic element in such a way of concealing itself. This study is intended to analyze the Byulseo Jeongwon which formed many relations with the nature and the residential space, thereby identifying the expression characteristics of eco-aesthetic sustainable architect. This study offers the answers with regard to the coexistence of the expression characteristics of sustainable architecture with the nature, space and the human from eco aesthetic viewpoint as well as the solution in dealing with the ecological and environmental challenges. Furthermore, it suggested the possibility that the traditional space would possibly be succeedable in new and creative way and sought the way for coexistence among the nature, space and human and eco aesthetics, and finally paved the pivotal foundation as the sustainable design alternative in future.

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Modeling of Energetic Neutral Atom (ENA) Emissions During a Magnetic Storm for CINEMA/TRIO

  • Lee, Ensang;Kwon, Hyuk-Jin;Park, Jong-Sun;Seon, Jongho;Jin, Ho;Kim, Khan-Hyuk;Lee, Dong-Hun;Wang, Linghua;Lin, Robert P.;Parks, George K.;Sample, John;Roelof, Edward C.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.117.1-117.1
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    • 2012
  • Energetic neutral atoms (ENAs) are emitted by charge exchange collisions between energetic ions and cold neutral atoms. ENAs can be used as an alternative measure of the energetic ions in the source region because they maintain the energy and pitch angle of the source energetic ions. In the present study we present simulation results of the ENA emissions during a magnetic storm to be measured by the STEIN instrument onboard the CINEMA/TRIO satellites. The CINEMA/TRIO mission consists of three identical cubesats with low-altitude orbits. The STEIN instrument onboard each cubesat can measure ENAs with energies from ~4 keV to ~20 keV as well as suprathermal electrons and ions. The measurement of ENA emissions from ring current by STEIN is simulated using the models for energetic ring current ions and geocoronal neutral atoms. Especially we will discuss about the energy spectrum of the ENAs and the effect of transient variations of the ring current.

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COSMIC RAYS ACCELERATED AT SHOCK WAVES IN LARGE SCALE STRUCTURE

  • RYU DONGSU;KANG HYESUNG
    • Journal of The Korean Astronomical Society
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    • v.37 no.5
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    • pp.477-482
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    • 2004
  • Shock waves form in the intergalactic space as an ubiquitous consequence of cosmic structure formation. Using N-body/hydrodynamic simulation data of a ACDM universe, we examined the properties of cosmological shock waves including their morphological distribution. Adopting a diffusive shock acceleration model, we then calculated the amount of cosmic ray energy as well as that of gas thermal energy dissipated at the shocks. Finally, the dynamical consequence of those cosmic rays on cluster properties is discussed.