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홍원표;윤중만
- Geotechnical Engineering
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- v.11 no.1
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- pp.63-78
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- 1995
Recently, in order to utilize more effectively underground space, deep excavations have been performed on building or subway construction in urban areas. In such excavations, anchors have been used to support the excavation retaining walls because the anchored excavation could provide wide working space for underground construction. The purpose of this paper is to establish empirical equations to be able to estimate the earth pressures acting on anchored excavation retention walls, based on the investigation of field measuring results, which were obtained from twenty seven building construction sites. The prestressed anchor force was measured by load cells which were attached to the anchor head, while the horizontal displacement of excavation walls were measured by inclinometers which were installed right'behind the retention walls. The lateral earth pressures acting on the anchored retention walls, which were estimated from both the measured anchor forces and the horizontal displacement of the walls, showed a trapezoidal distribution. There was some difference between the measured earth pressures acting on the anchored retention walls and the empirical earth pressures given by several empirical equations. Thus, the lateral earth pressures acting on anchored retention walls would be estimated by these empirical equations with some modifications.
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Lee, Jae-Jin;Kim, Kyung-Chan;Hwang, Jung-A;Kim, Yeon-Han;Park, Young-Deuk
- The Bulletin of The Korean Astronomical Society
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- v.37 no.1
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- pp.89.2-89.2
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- 2012
Radiation Belt, discovered by Van Allen in 1958, is a region energetic particles are trapped by the Earth's magnetic field. To measure charged particles and fields in the radiation belt, RBSP(Radiation Belt Storm Probes) mission will be launched in September 2012 by NASA. RBSP mission consists of two spacecraft having orbit from 600 km to 30,000 km and rotates the Earth twice a day. This mission is not designed just for scientific purpose but have operational function broadcasting real time data for space weather monitoring. As a program of KASI-NASA cooperation, KASI is constructing RBSP data receiving antenna that will be installed by April in Daejeon. With this antenna system, NASA can receive RBSP data for 24 hours and KASI also get space weather information to protect Korean GEO satellites. In this presentation, we will discuss how we use RBSP data for space weather forecasting. In addition, we will talk about science topics that can be achieved by RBSP mission. Especially we focus on the dusk-side electron precipitation that has been considered as a main mechanism of electron dropout events. We show the dusk-side precipitation is closely associated with radiation belt electron loss with NOAA-POES data, and why RBSP mission is important to understand radiation belt physics.
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최규홍;박종욱;서영수;경재만;이현주
- Journal of Astronomy and Space Sciences
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- v.8 no.2
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- pp.141-148
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- 1991
In order to obtain a complete picture of the time dependent dynamic of 360 fragments in space, the program IODS (ISSA Orbit Determination System) has been set up. Using The program IODS, all fragments orbits of one break-up event can be generated. Perturbations due to the Earth's asymmetrical potential, the Sun, moon, air drag and solar radiation force are considered. We summarize our results as follows : I) Due to J2 term, precessional motion of all fragment orbits are (수식생략) ii) The other perturbations have very small effects.
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Kim, Chul-Hee
- Journal of Astronomy and Space Sciences
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- v.4 no.2
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- pp.89-94
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- 1987
By using the recently determined color excess and distance data of classical by Kim (1985), the distribution of interstellar reddening material was studied to see the general picture of the average rate of interstellar absorption out to about 7-8 kpc in the Galactic plane in various directions from the sun.
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