• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.596-600
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• 1989

The simple and mixed ligand complexes of cadmium-oxalate-citrate systems have been studied with differential pulse polarography at 25${\circ}$C, in the solution with constant ionic strength, ${\mu}$= 1.0 ($NaNO_3$) and pH 8.0. Using the graphical methods by DeFord-Hume and Schaap-McMasters, the overall stability constants for the mixed ligand complexes, $\beta_{ij}$, were found to be: $log\beta_{11}$ = 4.91, $log\beta_{12}$ = 4.99, and log $log\beta_{21}$ = 5.18, respectively. Various equilibria involved in the mixed system have also been discussed.

• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.9-16
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• 2007

The influence of round length on the tunnel stability and construction cost is well acknowledged by many researchers and engineers but the coherent procedure is not available for its determination. In this study, the behaviour modes of the face and unsupported span was investigated for weak rock tunnel by a small scale model test, PFC3D and FDM analyses in consideration of the round length. Total five types of behaviour modes are defined and quantitative estimation of the behaviour modes was established in terms of the safety factor for the face stability and the conditional chart. Although the proposed method has some restrictions, this method can provide useful information for the optimization of the round length and excavation, especially in design stage.

• Land and Housing Review
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• v.2 no.2
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• pp.189-194
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• 2011

To reinforce bearing capacity-changed section or different foundation in the same building, empirical or simple tools have been used. To solve this problem, we suggest the analytical solution that can evaluate and reinforce the stability of foundation. To estimate the effect of reinforcement by replacement in different foundation, soil stiffness evaluation method taking into account the influence factor with respect to depth beneath the foundation need to be applied. In this paper, graphs and relevant formulae are suggested to calculate equivalent soil reaction coefficient showing the effect of reinforcement by crushed stone and lean concrete replacement.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.479-486
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• 2000

There has been recently an on-going effort in railway community to improve the dynamic performance of on-site railroad track with limited track possession time. In this paper, train running test lateral resistant force test and static/dynamic analyses are conducted before and after sprinkle of the ballast stabilizer in order to investigate the dynamic behaviors and parameters of the railroad track. Based upon the above results, effects of the stabilizer is verified, and a table for the track modulus representing on-site track condition and the methods to reduce the vibration and the transmitting forces of the ballasted track components to the infrastructures are suggested. It is thought that the suggestions made in this paper could be used as the preliminary data for the condition assessment and the maintenance of the track in the future.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2001.06a
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• pp.132-132
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• 2001

옥천변성대의 충주-황강리 지역내 앰피볼라이트의 기원암은 염기성 화성암으로 쏠레이아이트 계열의 변이질암에 속한다. Fe $O^{*}$/MgO값의 변화에 대하여 분별작용에 의해 영향을 받는 주성분 원소와 미량원소들의 변화를 보게되면 Ti $O_2$, Fe $O^{*}$와 불호정성 원소(incompatible element)인 Zr, Nb, Hf, Ta, Th 등은 분별작용동안 증가하는 반면 호정성 원소(compatible element)인 MgO, $Al_2$ $O_3$, Ni, Cr 등은 감소하는 경향을 보여주고 있다. Fe $O^{*}$/MgO, Ti $O_2$ 그리고 Fe $O^{*}$는 심해성 쏠레이아이트 영역으로부터 분화된 경향을 나타내 주고 있다. Ni, Cr은 Fe $O^{*}$/MgO값의 증가에 따라 급속히 감소하며 안정한 대륙과 해저화산의 영역에 도시되고 있으며 칼크-알칼리(CA)와는 관계가 없고 쏠레이아이트의 영역에서 변화 패턴을 보여주어 앰피볼라이트가 활동적인 대륙연변부의 지구조 환경보다는 안정한 대륙이나 해저화산과 관계가 더 있음을 시사한다. 경휘토류 원소(LREE)는 중휘토류 원소(HREE)에 비해 더욱 부화된 특성을 띠고 원자번호가 증가하면서 표준화된 휘토류 원소패턴의 경사가 점차 감소하는 경향을 보여주고 있다. 대부분의 시료들은 큰 Eu이상치를 갖고 있지 않아 마그마 정출 과정동안 사장석의 분별작용이 거의 수반되지 않았음을 지시하고 전체적인 휘토류 원소의 패턴은 거의 평행하게 나타나므로 기원 마그마가 유사함을 의미하고 있다. 비유동성 원소를 이용한 여러 판별도표들을 통해서 본암은 대륙성 현무암질암으로서 판내부 환경에서 유래되었으며 대륙내부 열곡의 알칼리 현무암과 대륙성 현무암 영역에 속하는 것으로 보아서 대륙지각내 열곡작용과 같은 장력운동에 수반되어 생성된 것임을 시사해 주고 있다. 앰피볼라이트의 지각혼성화를 평가하기 위해 이에 필요한 몇 개의 지화학적 매개변수를 계산한 결과 La/Ta, La/Nb, Nb/Th들의 값이 오염 안된 마그마의 값을 지시해 주어 본암이 지각혼성화 작용을 받지 않은 것으로 나타났다. 대부분의 시료들은 P-타입 MORB의 영역에 속하며 소수의 시료가 T-타입 MORB의 영역에 도시되고 있어 본 앰피볼라이트의 생성에는 양적으로 다른 두 가지의 유사한 마그마가 수반된 것으로 추정된다. 것으로 추정된다.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.789-794
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• 2015

In this study, we investigated the stability with respect to the Langmuir-Blodgett(LB) monolayer films of stearic acid and phospholipid(L-${\alpha}$-dimyristoylphosphatidyl choline, DMPC) mixture. LB films of stearic acid and DMPC monolayer were deposited by the LB method on the indium tin oxide(ITO) glass. The electrochemical properties measured by cyclic voltammetry with three-electrode system in $0.05N\;NaClO_4$ solution, -0.3 V initial, 1650 mV switching potential and -1350 mV final potential. As a result, monolayer LB films of stearic acid and phospholipid mixture was appeared on irreversible process caused by the oxidation current from the cyclic voltammogram. Diffusion coefficient (D) of stearic acid and DMPC mixture(molar ratio 1:1, 1:2, 1:3) was calculated $1.4{\times}10^{-3}$, $1.7{\times}10^{-3}$ and $1.6{\times}10^{-3}(cm^2/s)$ in $0.05N\;NaClO_4$ solution, respectively.

• Journal of the Korean Geotechnical Society
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• v.37 no.7
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• pp.5-12
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• 2021

When drilling investigations for Rock Slopes are not possible, it is often difficult to calculate the Ground Design Constants required for the Limit Equilibrium Analysis. Therefore, the outcrops or partially cutted Rock Slopes were analysed using JRC and JCS that can be easily and conveniently measured. In particular, the effect of the JRC on the Safety Factor or the Rock Slopes was analyzed intensively, and the results were presented as a relationship formula and Table. When the Rock slope was stable, the JRC increased by an average of 9.0% as the slope height increased, and increased by an average of 29.8% as the slope angle increased. JRC was more sensitive to slope angle changes. The Cohesion corresponding to JRC was calculated from JRC-Fs formula. JRC and Cohesion showed a nonlinear relationship, and the Cohesion was about 8.0% more sensitive to slope height changes than slope angle changes.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.332-344
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• 2007

Various geophysical well logs have been made along the four deep wells in Pohang, Gyeongbuk. The primary focus of geophysical well loggings was to improve understanding the subsurface geologic structure, to evaluate in situ physical properties, and to estimate aquifer production zones using fluid temperature and conductivity gradient logs. Especially natural gamma logs interpreted with core logs of borehole BH-1 were useful to discriminate the lithology and to determine the lithologic sequences and boundaries consisting of semi-consolidated Tertiary sediments and intrusive rocks such as basic dyke and Cretaceous sediments. Cross-plot of physical properties inferred from geophysical well logs were used to identify rock types such as Cretaceous sandstone and mudstone, Tertiary sediments, rhyolite, and basic dyke. The temperature log indicated $82.51^{\circ}C$ at the depth of 1,981.3 meters in borehole BH-4. However, considering the temperature of borehole BH-2 measured under stable condition, we expect the temperature at the depth in borehole BH-4, if it is measured in stable condition, to be about 5 or $6^{\circ}C$ higher. Several permeable fractures also have been identified from temperature and conductivity gradient logs, and cutting logs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.702-708
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• 2016

The railway signaling system has evolved to maximize its safety and maintainability based on the experiences in the construction and operation of railway systems. The newly developed systems was established to cope with the changes in an operating environment. In the process of a transition to the new system, both the existing ATS (Automatic Train Stop) and new ATP/ATO (Automatic Train Protection/Automatic Train Operation) systems are operating simultaneously in parallel. In this situation, modifications of the conditions of the interlocking diagram and logic are necessarily required on the existing ATS systems due to the frequent improvements in signaling equipment. This paper reports the enhancement of safety and operational efficiency of the system through an improvement of the security and the interlocking conditions of the existing ATS systems. The independent display of signals for each track was ensured to avoid giving the effect of On/Off signals for the selected track on the opposite side, and the security was improved by adjusting the position and interlocking conditions. In addition, the increased traffic density of railway systems was achieved by removing the unnecessary conditions and detailed signal display, which resulted in enhanced operational efficiency.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.13-22
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• 2018

Aluminum silicates ($Al_2SiO_5$) undergo phase transitions among kyanite, andalusite, and sillimanite depending on temperature and pressure conditions. The minerals are often used as an important indicator of the degree of metamorphism for certain metamorphic rocks. In this study, we have applied classical molecular dynamics (MD) simulations and density functional theory (DFT) to the aluminum silicates. We examined the crystal structures as a function of applied pressure and the corresponding stabilities based on calculated enthalpies at each pressure. In terms of the lattice parameters, both methods showed that the volume decreases as the pressure increases as observed in the experiment. In particular, DFT results differed from experimental results by much less than 1%. As to the relative stability, however, both methods showed different levels of accuracy. In the MD simulations, a transition pressure at which the relative stability between two minerals reverse could not be determined because the enthalpies were insensitive to the applied pressure. On the other hand, in DFT calculations, the relative stability relation among the three minerals was consistent with experiment, although the transition pressure was strongly dependent on the choice of the electronic exchange-correlation functional.