• Journal of Environmental Science International
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• v.4 no.1
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• pp.41-52
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• 1995

The effects of reaction temperature, SO2 and CO2 concentration in an air gas stream, particle sizes of limestone on the reactivity and capacity of SO2 removal have been determined in a thermogravimetric analyser(TGA). The apparent reaction order of sulfation reaction of pre-calcined lime(CaO) with respect to SO2 is found to be close to unity. The apparent activation energies are found to be 17,000 kcal/kmol for sulfation of pre-calcined lime and 19,500 kcal/kmol for direct sulfation of limestone(CaCO3). The initial sulfation reaction rate of pre-calcined lime increases with increasing temperature, whereas the sulfur capture capacity exhibits a maximum value at 90$0^{\circ}C$. In direct sulfation of limestone, sulfation reactivity and sulfur capature capacity of sorbent increase with increasing temperature and decreasing CO2 concentration in a gas bulk stream. The main pare of pre-calcined lime is shifted to the larger pore sizes and pore volume decreases with increasing sulfation time and temperature. The surface area of lime decreases with increasing calcination temperature under an air atmosphere, whereas is yearly constant under a CO2(5, 10%) atmosphere in a gas stream.

• Bulletin of the Korean Chemical Society
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• v.16 no.12
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• pp.1189-1193
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• 1995

The comparative molecular field analysis (CoMFA) method has been employed to correlate the apparent lipophilicity (logkw) and global lipophilicity (logP) for orthopramide derivatives. This study demonstrated that CoMFA is an excellent method in predicting the complex properties of molecules such as apparent lipophilicity (logkw) or lipophilicity (logP). The better predictability of lipophilicity by introducing logkw as an independent descriptor suggests that the HPLC capacity factor measured in a buffer of pH 7.5 (logkw) can be effectively utilized in the prediction of global lipophilicity.

• Journal of the Korean institute of surface engineering
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• v.28 no.2
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• pp.92-100
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• 1995

To increase the capacity of positive electrode materials for matching the high capacity negative electrode materials in alkaline rechargeable batteries, high-density nickel hydroxide powders were made through a continuous process from nickel sulfate reacted with ammonia and sodium hydroxidc. The effect of operating conditions on structure, shape, size distribution, apparent density and tap density of powders were investigated. Crystal structure of nickel hydroxide powder was hcp according to Bravais Lattice. The increase of mean residence time promoted the growth of (101) plane. The shape of powder was nearly spherical. Their size was in the range of $2~50\mu\textrm{m}$. The size distribution of the powders prepared was narrower than that of commercially obtained nickel hydroxide. Apparent density and tap density were 1.6~1.7g/cc and 2.0~2.1g/cc, respectively.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.643-650
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• 1995

A numerical method for treating transient diffusion Involving change of phase is presented. In other methods of dealing with this class of problems, the mass flux balance at the moving phase boundary requires explicit treatment of two distinct phases. The technique, originating from the apparent heat capacity method in transient heat conduction with the phase change, avoids the difficulty by transferring the concentration discontinuity at the boundary to smoothed physical property variations near the moving front. This technique accomodates the nonlinearities which preclude use of analytical solutions. It was tested against known analytical solutions for simple cases and turned out to be quite accurate.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.41-54
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• 2023

The use of a skirt, a vertical projection attached to the footing, is a recently developed method to increase the bearing capacity of soils and reduce foundation settlements. Most of the studies were focused on vertical skirted circular footings resting on clay while neglecting the rigidity and inclination of skirts. This study employs finite element limit analysis to investigate the bearing capacity enhancement of flexible and rigid inclined skirts in cohesionless soils. The results indicate that the bearing capacity initially improves with an increase in the skirt inclination but subsequently decreases for both flexible and rigid skirts. However, the rigid skirt exhibits more apparent optimum skirt inclination and bearing capacity enhancement than the flexible one, owing to differences in their failure mechanisms. Furthermore, the bearing capacity of the inclined skirted foundation increases with the skirt length, footing depth, and internal friction angle of the soil. In the case of rigid skirts, the bearing capacity increases linearly with skirt length, while for flexible skirts, it reaches a stable value at a certain skirt length. The efficiency of the flexible footing reduces as the footing depth and soil internal friction angle increase. Conversely, the efficiency of the rigid skirt decreases only with an increase in the depth of the footing. The paper also presents a detailed analysis of various failure patterns, highlighting the behaviour of inclined skirted footings. Additionally, nonlinear regression equations are provided to quantify and predict the bearing capacity enhancement with the inclined skirts.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.106-114
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• 2009

This present study was conducted to investigate photosynthetic characteristics, chlorophyll fluorescence, chlorophyll contents of Allium victorialis var. platyphyllum, Ligularia fischeri, Ligularia stenocephala growing under four different light intensity regimes (full sun, and 64~73%, 35~42%, 9~16% of full sun). Three wild vegetables showed good photosynthetic capacity in July. Allium victorialis var. platyphyllum showed best photosynthetic capacity and apparent quantum yield in 35~42% of full sun. But Ligularia fischeri and Ligularia stenocephala showed best photosynthetic capacity and apparent quantum yield in full sun and decreased as the shading level increaese. As the shading level increased, the total chlorophyll contents increased with a significant difference in three wild vegetables.

• Steel and Composite Structures
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• v.41 no.5
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• pp.681-695
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• 2021

Many existing transmission or communication towers designed several decades ago have undergone nonreversible performance degradation, making it hardly meet the additional requirements from upgrades in wind load design codes and extra services of electricity and communication. Therefore, a new-type non-destructive reinforcement method was proposed to reduce the on-site operation of drilling and welding for improving the quality and efficiency of reinforcement. Six built-up steel angle members were tested under compression to examine the reinforcement performance. Subsequently, the cyclic loading test was conducted on a pair of steel angle tower sub-structures to investigate the reinforcement effect, and a simplified prediction method was finally established for calculating the buckling bearing capacity of those new-type retrofitted built-up steel angles. The results indicates that: no apparent difference exists in the initial stiffness for the built-up specimens compared to the unreinforced steel angles; retrofitting the steel angles by single-bolt clamps can guarantee a relatively reasonable reinforcement effect and is suggested for the reduced additional weight and higher construction efficiency; for the substructure test, the latticed substructure retrofitted by the proposed reinforcement method significantly improves the lateral stiffness, the non-deformability and energy dissipation capacity; moreover, an apparent pinching behavior exists in the hysteretic loops, and there is no obvious yield plateau in the skeleton curves; finally, the accuracy validation result indicates that the proposed theoretical model achieves a reasonable agreement with the test results. Accordingly, this study can provide valuable references for the design and application of the non-destructive upgrading project of steel angle towers.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.36-48
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• 2010

This present study was conducted to investigate photosynthetic characteristics, chlorophyll fluorescence, chlorophyll contents of Betula platyphylla var. japonica, Prunus leveilleana, Magnolia sieboldii, growing under four different light intensity regimes (full sun, and 64~73%, 35~42%, 9~16% of full sun). As result, Betula platyphylla var. japonica showed outstanding photosynthetic capacity and apparent quantum yield in full sun and showed low shade tolerance. Prunus leveilleana showed good photosynthetic capacity and apparent quantum yield in 64~73% or 35~42% of full sun and showed common shade tolerance. However, Magnolia sieboldii showed good photosynthetic capacity and apparent quantum yield in 35~42% of full sun, while the lowest in full sun. Magnolia sieboldii showed the highest shade tolerance compared to the other species. As the shading level increased, the total chlorophyll contents of all species increased with significant difference.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.605-612
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• 2005

In this study, the possible use of HMDA (Hexamethylenediamine) as additive to enhance reaction between $CO_{2}$ and AMP (2-amino-2-methyl-1-propanol) which has higher absorption capacity than that of MEA (Monoethanolamine) was investigated. Also, the absorption capacity for $CO_{2}$ was compared with addition of HMDA, piperazine or MDEA (N-methyldiethanolamine) into $30\;wt\%$ AMP at $40^{circ}C$ and $CO_{2}$ partial pressure ranging from 0.5 to 120 kPa. Apparent rate constant ($K_{app}$) and absorption capacity with the addition of $5\∼20\;wt\%$ HMDA into AMP increased $214.2\∼276.3\%$ and $29.9\∼91.7\%$ than those of AMP alone. As a result, when $5\;wt\%$ HMDA added into AMP, the increasing rate of the absorption rate and the absorption capacity was found to be the highest. In addition, the absorption capacity increased $6.8\%,\;9.8\%,\;11.6\%$ with addition of MDEA, piperazine or HMDA respectively as compared to AMP alone at $CO_{2}$ partial pressure of 20 kPa. Consequently, HMDA as additive to improve absorption capacity of AMP was superior to other additives.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.552-560
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• 2004

Stone column is a soil improvement method and can be applicable for loose sand or weak cohesive soil. Since the lack of sand in Korea, stone column seems one of the most adaptable approach for poor ground as a soil improvement method. However, this method was not studied for practical application. In this paper, the most effective design parameters for the being capacity of stone column were studied. The parametric study of major design factors for single stone column was carried out under the bulging and general shear failure condition, respectively. Especially, a test result of single stone column by static load was compared with the bearing capacity values of suggested formulas. The analysis result showed that the ultimate bearing capacity by the formula was much less than the measured value by the static load test. Especially, the result of the parametric study under general shear failure condition showed that the bearing capacity has apparent difference between each suggested formulas with the variation of the major design parameters. Therefore, the result of this study can be a suggestion which is applicable for the field test and the future research.