• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.148-158
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• 1998

The aims of this study are to evaluate the application on the stress-strain behavior of granite Soil using Lade's double work hardening constitutive model based on the theories of elasticity and plasticity. From two different sites of construction work, two disturbed and compacted weathered granite samples which are different in partical size and degree of weathering respectively were obtained. The specimen employed were sampled at Iksan and Pochon in order to predict the constitutive model. Using the computer program based on the regression analysis, 11 soil parameters for the model were determined from the simple tests such as an isotropic compression-expansion test and a series of drained conventional triaxial tests. In conclusion, it is shown that Lade's double work hardening model gives the good applicability for processing of stress-strain, work-hardening, work-softening and soil dilatancy. Therefore, this model in its present form is applicable to the compacted decomposed granite soil.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.125-126
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• 2010

In this study is analysis of infill walls fiber volume fraction and reduced the inside cross-section of strain-hardening cement composite(SHCC) infill walls is to evaluate seismic performance experimentally.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.55-56
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• 2010

Infill walls have been investigated experimentally and theoretically by many researchers during last decades. The objective of this research is to evaluate structural strengthening performance of lightly reinforced concrete with reduced the inside cross-section of Strain-hardening cement composites(SHCC) experimentally.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.184-185
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• 2019

Korea has defined fine dust as a social disaster as the problem of fine dust and air pollution becomes serious. Fine dust is classified as class one carcinogens because it is harmful to human body. When fine dusts enter the human body, they cause bronchial and skin diseases such as respiratory allergies, irritable pneumonia, asthma and atopy. As the air pollution becomes serious, the government is demanding measures to reduce fine dust. The polluted air in the outdoor is introduced into the room, thereby increasing the pollution degree of the indoor air quality. In this study, an adsorption type matrix for the improvement of indoor air quality was produced. Magnesium oxide and magnesium chloride were used as binders and diatomaceous earth was used as a adsorption material.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.567-570
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• 2001

현재의 출입국 관리자는 여권을 제시하면 여권을 육안으로 검색하고 수작업으로 정보를 입력하여 여권 데이터베이스와 대비하는 것이다. 본 논문에서는 이러한 문제점을 해결하기 위하여 자동으로 여권을 인식할 수 있는 방법을 제안한다. 여권에는 사용자에 대한 많은 정보들이 있는데 여권 영상에서 코드 정보 영역을 히스토그램 방식과 소벨 연산자를 이용하여 코드 영역 및 개별 코드 문자를 추출하고 새로운 자가 생성 지도학습 알고리즘(Self-Generating Supervised Learning Algorithm)을 제안하여 여권 인식에 적응하였다. 10개의 여권 영상을 실험한 결과 모든 코드의 문자 영역이 추출되었고 인식되었다.

• Computational Structural Engineering
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• v.5 no.1
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• pp.119-132
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• 1992

The objective of this study is to perform extensive parametric studies of the lateral-torsional buckling of short 1-beams under repeated loadings, and to gain a further insight into the lateral-torsional beam buckling problem. A one-dimensional geometrically (fully) nonlinear beam model is used, which includes superposed infinitesimal transverse warping deformation in addition to finite torsional warping deformation. A multiaxial cyclic plasticity model is also implemented to better represent cyclic metal plasticity in conjunction with a consistent return mapping algorithm. The general response for the lateral-torsional buckling of short I-beams under repeated loadings is examined through several parametric studies around the standard case : the material yield strength, the yield plateau, the strain hardening, the kinematic hardening, the residual stresses, the load eccentricity with respect to the shear center, the height of the load with respect to the cross-section of the beam, the location of the load along the length of the beam, the dimensions of the cross-section of the beam and the fixity of the supported end remote from the load.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.215-228
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• 2002

In a companion paper. (Oh, 2002), the constitutive model, called GUX model, was implemented as a user subroutine in ABAQUS code, where the GUX model could describe the behavior of overall strain range. An accuracy analysis verified that the implicit stress integration maintained the accuracy of solutions successfully. Since the GUX model is an anistropic hardening elasto-plastic constitutive model based on total stress concept, geotechnical problems under fully drained or undrained condition can be analyzed after acquisition of stress-strain relationships from drained or undrained triaxial tests. This study includes the analyses of the stability of embankments on soft clays and weathered soils and the example of axially loaded soil-pile system. In the large deformation analyses, geometric nonlinearity was considered and the result of analyses with GUX model was compared with that of Mises model for the overall strain range behavior.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.925-934
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• 1994

Nickel recovered from the spent oil-hydrogenation catalysts was used in hydrogenation catalyst preparation. The spent catalyst contains approximately 21.8% Ni, 0.7% Mg, and small quantities of Al, Fe, and Zn. Nickel recovery was obtained by inorganic acid digestion in the order of HCI>$NHO_3$>$H_2SO_4$. For $HNO_3$, 3hour extraction with 3N solution was satisfactory. In the PH range of 6.5~9.0, Ni recovery was higher, but metallic impurities were found to be coprecipitated. The PH in the range of 7.0~9.0 seems to be the optimum condition for separation to obtain acceptable Ni precipitates without the decrease of purity. The catalysts prepared with reclaimed nickel by wet reduction methods showed catalytic activities close to those prepared using reagent nickel in the oil hydrogenation reaction. The surface areas of the support do not seem to affect the catalytic activity.

• Composites Research
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• v.35 no.2
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• pp.53-60
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• 2022

This study uses Diglycidyl ether of terephthalylidene-bis-(4-amino-3-methylphenol) (DGETAM), an amine hardener 4,4'-diaminodiphenylethane (DDE) and cationic catalyst N-benzylpyrazinium hexafluoroantimonate (BPH) to make epoxy film. For analysis, ¹H_NMR and FT-IR were used to verify proper synthesis, and the liquid crystallinity of DGETAM was checked using Differntial Scanning Calorimetry and Polarized Optical Microscopy. Thermal conductivity of the sample was measured using Laser Flash Apparatus. Thermal stability as well as thermal conductivity is important when used as a packaging material. Activated energy is the energy needed to generate a response, which can be used to estimate the energy required to maintain physical properties. It was obtained using the Arrhenius equation based on the data measured by isothermal decomposition using Thermogravimetric Analysis. Measurement of the thermal conductivity of epoxy films showed higher thermal conductivity when DDE was used, and it was found that thermal conductivity had an effect on thermal stability, given that it represented an activation energy similar to a film with BPH upon 5% decomposition.

• Journal of the Korean GEO-environmental Society
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• v.22 no.3
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• pp.5-13
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• 2021

Due to population growth and industrial development, the amount of industrial waste is increasing every year. In particular, in a thermal power plant using finely divided coal, a large amount of coal ash is generated after combustion of the coal. Among them, fly ash is recycled as a raw material for cement production and concrete admixture, but about 20% is not utilized and is landfilled. Due to the continuous reclamation of such a large amount of coal ash, it is required to find a correct treatment and recycling plan for the coal ash due to problems of saturation of the landfill site and environmental damage such as soil and water pollution. In recent years, the use of a fluid embankment material that can exhibit an appropriate strength without requiring a compaction operation is increasing. The fluid embankment material is a stable treated soil formed by mixing solidifying materials such as water and cement with soil, which is the main material, and has high fluidity before hardening, so compaction work is not required. In addition, after hardening, it is used for backfilling or filling in places where compaction is difficult because higher strength and earth pressure reduction effect can be obtained compared to general soil. In this study, the possibility of use of fluidized soil using high water content cohesive soil and coal ash is considered. And it is intended to examine the flow characteristics, strength, and bearing capacity characteristics of the material, and to investigate the effect of reducing the earth pressure when applied to an underground burial.