• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.302-302
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• 2006

• Journal of the Korean Society of Earth Science Education
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• v.8 no.1
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• pp.25-34
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• 2015

The objective of this study is to clarify how high school students recognize the mental model of the global environment and how they conceptualize the environment. Using the drawing and interview, 25 high school students participated in the survey and were asked to visualize the environmental elements of the global environment and describe the environment they portrayed. The dominant mental model in the present was Mental Model 3: the environment as a place impacted or modified by human activity. Yet, the partial mental model in the future was Mental Model 2: the environment as a place that supports human life. The implications to environmental science education are explored.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.743-749
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• 2009

In this study, the field test for suction drain method which does not require a surcharge load and a sealing sheet was performed at west seashore's site constructed by the dredged and reclaimed clay. The improvements of soft ground by suction drain method was analyzed by the results of real-time field measurement, SPT(Standard Penetration Test) and laboratory tests. The results indicated that the soft ground improvement is effective the vertical drain method used with vacuum pressure rather than surcharge load with considering settlements, dissipation of pore water pressure and shear strength.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.352-359
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• 2003

철도나 고속철도 교량에 사용되는 장대레일은 차량에 의한 동적충격의 완화, 주행시 승차감의 향상과 같은 장점을 가져온 반면에, 인접한 교량의 연결부에서 레일과 교량 상부구조간의 거동 불일치로 인해 레일에 부가적인 응력을 발생시킨다. 이러한 부가적인 레일응력과 지반운동의 특성에 따른 구조적 응답의 민감도 및 열차의 안전한 정지를 고려하여, 지진 발생시 고속철도교량의 장대레일 응력을 해석하기 위해 레일의 재료비선형성, 지반운동의 위상차 등을 고려한 비선형 시간이력해석 방법을 제시하였다. 그리고 우리나라의 여러 지반조건을 고려하고 고속철도의 대표적인 연속교량 모델에 적용하여 제시한 방법의 타당성을 검토하였다.

• Geomechanics and Engineering
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• v.8 no.4
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• pp.523-540
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• 2015

Based on limit equilibrium principles, this study presents a theoretical derivation of a new analytical formulation for estimating magnitude and lateral earth pressure distribution on a retaining wall subjected to seismic loads. The proposed solution accounts for failure wedge inclination, unit weight and friction angle of backfill soil, wall roughness, and horizontal and vertical seismic ground accelerations. The current analysis predicts a nonlinear lateral earth pressure variation along the wall with and without seismic loads. A parametric study is conducted to examine the influence of various parameters on lateral earth pressure distribution. Findings reveal that lateral earth pressure increases with the increase of horizontal ground acceleration while it decreases with the increase of vertical ground acceleration. Compared to classical theory, the position of resultant lateral earth force is located at a higher distance from wall base which in turn has a direct impact on wall stability and economy. A numerical example is presented to illustrate the computations of lateral earth pressure distribution based on the suggested analytical method.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.104-105
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• 2007

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• Journal of Astronomy and Space Sciences
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• v.31 no.1
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• pp.7-13
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• 2014

Variabilities in the solar wind cause disturbances throughout the heliosphere on all temporal and spatial scales, which leads to changeable space weather. As a view of space weather forecasting, in particular, it is important to know direct and indirect causes modulating the space environment near the Earth in advance. Recently, there are discussions on a role of the interaction of the solar wind with Mercury in affecting the solar wind velocity in the Earth's neighborhood during its inferior conjunctions. In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets' wake, by examining whether the interplanetary magnetic field and the proton density in the solar wind observed by the Advanced Composition Explorer (ACE) spacecraft, and the geomagnetic field via the Dst index and Auroral Electrojet index (AE index) are dependent upon the relative position of the inner planets. We find there are indeed apparent variations. For example, the mean variations of the geomagnetic fields measured in the Earth's neighborhood apparently have varied with a timescale of about 10 to 25 days. Those variations in the parameters we have studied, however, turn out to be a part of random fluctuations and have nothing to do with the relative position of inner planets. Moreover, it is found that variations of the proton density in the solar wind, the Dst index, and the AE index are distributed with the Gaussian distribution. Finally, we point out that some of properties in the behavior of the random fluctuation are to be studied.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.415-423
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• 2008

Earth outer core is composed of iron mainly with some diluent elements, which account for the observed ca. 10% density deficit compared to the pure iron. Among candidates as the light diluents, hydrogen and oxygen were selected, and the thermodynamic stability of the following reaction was calculated; hematite + hydrogen $\to$ goethite + iron. At ambient conditions, Gibb's free energy of this reaction is 12.62 kJ/mol. On increasing pressure at room temperature, it decreases to zero at 0.068 GPa. This energy decreases at constant rate down to 200 GPa, which shows -208.26 kJ/mol at that pressure. From these results, this chemical reaction prefers the reduction environment forming the iron element and iron oxyhydroxide, so possible presence of iron oxyhydroxide with iron at proto-core can not be ruled out.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.186-188
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• 2003

The Suryun gold-silver mine is one of precious metal occurrences discovered in the Hapcheon mineralized district on which lies the western margin of the Cretaceous Gyeongsang Basin, Korea. The district hosts deposits that include the early to late Cretaceous (108 ～ 88 Ma) Au-Ag-bearing vein systems (So et al. 1989; Shelton et al. 1990). (omitted)

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.166-171
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• 2008

We cannot imagine any more the environment and energy problems are separated from our lives. The various attempts to solve these problems are made all over the world. In this study it was performed to analyze a different heating and cooling load depending on the earth-sheltering method and kind of soils by using TRNSYS 16 as the first step to establish the design guidelines for earth-sheltered architecture, one of the eco-friendly and low energy consuming building types. After performing this simulation, we found the result like this. It is the most lowest load in case of all of walls and roof being earth-sheltered. But considering of the load reduction rate, the effect of earth-sheltering the exterior vertical wall is more efficient for load reduction than the one of earth-sheltering a roof. And we got a lower thermal load in case of a lower heat conductivity of soil. Afterwards we will conduct a further study for boundary condition at earth-sheltered surface and the simulation analysis about the sensitivity variables. The final goal of this study is preparing the design guidelines for earth-sheltered architecture. so we will contribute to building energy saving.