• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.3
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• pp.14-22
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• 2023

Steel-pipe civil structures, including steel-pipe energy piles and cast-in-place piles (CIPs), utilize steel pipes as their primary reinforcements. These steel pipes facilitate the circulation of a working fluid through their annular crosssection, enabling heat exchange with the surrounding ground formation. In this study, the cooling performance of a ground source heat pump (GSHP) system that incorporated steel-pipe civil structures was investigated to assess their applicability. First of all, the thermal performance test was conducted with steel-pipe CIPs to evaluate the average heat exchange amount. Subsequently, a GSHP system was designed and implemented within an office container, considering the various types of steel-pipe civil structures. During the performance evaluation tests, parameters such as the coefficient of performance (COP) and entering water temperature (EWT) were closely monitored. The outcomes indicated an average COP of 3.74 for the GSHP system and the EWT remained relatively stable throughout the tests. Consequently, the GSPH system demonstrated its capability to consistently provide a sufficient heat source, even during periods of high cooling thermal demand, by utilzing the steel-pipe civil structures.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.488-492
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• 2023

In this study, a carbon film derived from a polymer/lignin composite precursor was produced by a carbonization cycle with a controlled temperature profile. The feasibility of successful formation of the carbon film using the carbonization cycle was monitored. The adsorption behavior of the carbon film toward various molecules, such as nonpolar and polar organic molecules, and dyes was investigated using ultraviolet/visible (UV/Vis) spectroscopy compared with that of carbonized lignin. Cyclic voltammetry (CV) analysis proved that a robust carbon film was prepared by the carbonization cycle. It was also demonstrated that the carbonized lignin and carbon film showed adsorption capability toward all types of organic molecules, in particular organic dyes, owing to the carbonized lignin. This work provides important information for future relevant research.

• Journal of the Mineralogical Society of Korea
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• v.31 no.2
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• pp.113-121
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• 2018

Baekasan Acheon cave located in Hwasun-gun, Jeollanam-do is a natural limestone cave only found in this province. In this study, the mineralogical and geochemical characteristics of speleothems collected from Baekasan Acheon cave were identified and the capability of carbonate mineral formation by aerobic microorganisms enriched from the cave and the mineralogical and geochemical characteristics of carbonate minerals formed by the microorganisms were investigated. The samples of sediments (clay) and speleothems (shelfstone and cave coral) were collected at three sites in the cave. The samples of shelfstone and cave coral were identified mainly as carbonate mineral, Mg-rich calcite, and clay minerals were composed of quartz, muscovite, and vermiculite by X-ray diffraction (XRD) analysis. To cultivate the carbonate forming microorganisms, parts of the sediment and speleothems were placed in D-1 medium containing urea, respectively, and the growth of microorganisms was observed under the aerobic condition at room temperature. The capability of carbonate mineralization of the cultured Baekasan Acheon cave microorganisms was examined through adding 1% (v/v) of the cultured microorganisms and calcium sources, Ca-acetate or Ca-lactate, into the D-1 medium. XRD analysis showed that the microorganisms cultured in cave deposits formed calcium carbonate ($CaCO_3$) under all conditions, and these microbial carbonate minerals included calcite and vaterite. The morphological characteristics and chemical composition of biologically formed minerals were observed by SEM-EDS showed various crystal forms such as rhomboid, spherical, perforated surface with Ca, C, and O of major chemical components. The existence of such microorganisms in the cave can contribute the formation of carbonate minerals, and it is likely to affect the geochemical cycles of carbon and calcium in the cave.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.3
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• pp.191-209
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• 2023

Amid rapid changes in technological innovation due to the influence of the 4th Industrial Revolution and COVID-19, research related to absorption capacity and patent activities to promote technological innovation of Korean technology start-ups is important in this uncertain environment. This study aims to examine the effects on entrepreneurial performance and patent activities by reconstructing absorptive capacity, an organizational capability, for technology-based startups in fields such as BT and ICT with less than seven years of establishment, distinguishing between potential absorptive capacity and realized absorptive capacity. The study also seeks to develop a theoretical research model. To accomplish this, data was collected from managerial executives, including CEOs of 215 technology startups. The following hypotheses were tested: Firstly, potential absorptive capacity had a significant impact on patent activities, while realized absorptive capacity did not. Secondly, potential absorptive capacity had a significant impact on technological performance, while realized absorptive capacity did not. Thirdly, both potential and realized absorptive capacity had a significant impact on financial and non-financial performance. Fourthly, patent activities indirectly influenced potential absorptive capacity and technological performance, but did not affect realized absorptive capacity. Fifthly, patent activities indirectly influenced potential absorptive capacity and financial performance, but did not affect realized absorptive capacity. Lastly, patent activities indirectly influenced potential absorptive capacity and non-financial performance, but did not affect realized absorptive capacity. The practical significance of this study lies in providing useful guidelines for building the core capabilities of organizations through absorptive capacity and patent activities. Furthermore, it is expected that startups that have not recognized the formation process of absorptive capacity for patent activities will perceive the formation mechanism of absorptive capability anew and show considerable interest in future potential and realized absorptive capacity as part of their management strategies. This is anticipated to play an important role in adapting to rapidly changing technological advancements, the startup ecosystem, and securing sustainable competitive advantages.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.197-204
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• 1987

In order to know the growth of suspended cells by explant sources, the change of nitrogen contents of cultured cells following the growth periods, capability of micro-callus formation according to cell plating methods, growth of suspended cells on various media, and efficiency of micro-callus formation by using growth regulators and different N strengths were investigated. 1. When suspension culture was tried by using the callus induced from internode and petiole, cell fresh weight and packed cell volume increased with similar way and the growth reached at stationary phase after 12 culture days. 2. N-contents of cultured cells increased upto 3 days and decreased around 6days. But the values increased again upto 9 days, after that they showed gradual decreases. 3. Of cell plating methods, embedding method was the best for micro-callus formation. 4. Growth of suspened cells showed the rest performanoes, when they were cultured on LM medium with 1/2N strengths and BAP 0.01.2.4-D 0.1, and NAA $1.0mg/{\ell}$, after 15 cultured days(upto 76.9 folds). LM medium was better than MS or GD. The combination of auxin and cytokinin was better for cell growing than auxin-treatment only. 5. Micro-callus from single cell and small cell aggregates was formed only on MS and LM media with 2,4-D $1.0mg/{\ell}$.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.51-59
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• 2001

Column and box tests were performed to investigate the removal efficiency of NAPL using the surfactant enhanced flushing In heterogeneous medium. Homogeneous Ottawa sand and heterogeneous soil were used to verify the increase of remediation efficiency for the surfactant enhanced flushing in column test. Box tests with two different heterogeneous sub-structure were performed to quantify the capability of the surfactant enhanced flushing as a remediation method to remove NAPL from the heterogeneous medium. Two different grain size sand layers were repeated in the box to simulate the heterogeneous layer formation and the modified fault structure was built to simulate the fault system in the box. O-xylene as a LNAPL and PCE as a DNAPL were used and oleamide as a non-ionic surfactant. The maximum NAPL effluent concentration with 1% oleamide flushing in the homogeneous column test increased about 460 times compared to that with only water flushing and about 250 times increased in the real soil column test. In heterogeneous medium, the maximum effluent concentration increased about 150 times in 1% oleamide flushing and most of NAPL were removed from the box within 8 pore volume flushing, suggesting that the removal efficiency increased very much compared to in only water flushing. Results investigated the capability of the surfactant enhanced remediation method to remove NAPL even in heterogeneous medium.

• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.368-372
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• 2008

This study evaluates the usefulness and capability of surface electrical resistivity technique for identifying the weak zones or subsurface cavities in karst area with limestone formation. Weak zones or cavities near surface can be potentially dangerous and several problems are associated with collapse of roads or buildings accompanied by subsidence phenomena. In this paper, both two and three dimensional resistivity investigation were conducted to investigate subsidence along a road in Yongweol-ri, Muan-gun, South Korea. The results of the resistivity survey using dipole-dipole array provide a clear view of the weathered regolith, the distribution of weak zones or cavities and bedrock. Several low resistivity areas were identified and subsequent drilling led to the discovery of several weak zone or clay-filled underground cavities. The drilling results show excellent correlation with the resistivity images. It is illustrated, the ability of electrical technique to produce high resolution images of subsurface, which are useful for subsidence assessment. Also the results of this study have demonstrated that two and three dimensional electrical resistivity surveys are useful for delineating the subsidence area. Based on resistivity imaging, the map of hazardous zone has been developed.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.193-201
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• 2000

Partitioning of hydrophobic organic compounds (HOCs) to a biosurfactant, hydroxypropyl-${\beta}$-cyclodextrin (HPCD), was conducted to evaluate the feasibility of using HPCD to remove HOCs from soil/groundwater. HOC partitioning to HPCD was very fast, with over 95% of the complexation occurring within 10 min. Some influence of solution chemistry and HOC concentration on HOC-HPCD complex formation coefficients was observed. HPCD sorption on soil as quantified by both a fluorescence technique and total organic carbon measurements was negligible, indicating no significant affinity of HPCD for the solid phase. Although the HOC solubilization capability of HPCD was lower than that of synthetic surfactants such as SDS and Tween 80, HPCD can be effective in removing sorbed HOCs from a model subsurface environment, primarily because of its negligible sorption to the solid phase (i.e., all the HPCD added facilitates HOC elution). However, in contrast with conventional surfactants, HPCD becomes relatively less effective for HOC partitioning with increasing HOC size and hydrophobicity. Therefore, comparisons between HPCD and synthetic surfactants for enhanced remediation applications must consider the specific HOC(s) present and the potential for surfactant material losses to the solid phase, as well as other more generally recognized considerations such as material costs and potential toxicological effects.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.54.3-54.3
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• 2015

To probe the star formation in local and early Universe, the NISS with a capability of imaging spectroscopy in the near-infrared is being developed by KASI. The main scientific targets are nearby galaxies, galaxy clusters, star-forming regions and low background regions. The off-axis optical design of the NISS with 15cm aperture was optimized to obtain a wide field of view (FoV) of $2deg.{\times}2deg.$ as well as a wide spectral coverage from 0.9 to $3.8{\mu}m$. The opto-mechanical structure was designed to be safe enough to endure in both the launching condition and the space environment. The dewar will operate $1k{\times}1k$ infrared sensor at 80K stage. The NISS will be launched in 2017 and explore the large areal near-infrared sky up to $200deg.^2$ in order to get both spatial and spectral information for astronomical objects. As an extension of the NISS, KASI is planning to participate in a new small space mission together with NASA. The promising candidate, SPHEREx (Spectro-Photometer for the History of the Universe Epoch of Reionization, and Ices Explorer) is an all-sky survey satellite designed to reveal the origin of the Universe and water in the planetary systems and to explore the evolution of galaxies. Though the survey concept is similar to that of the NISS, the SPHEREx will perform the first near-infrared all-sky imaging spectroscopic survey with the wider spectral range from 0.7 to $5{\mu}m$ and the wider FoV of $3.5deg.{\times}7deg.$ Here, we report the current status of the NISS and introduce new mission for the near-infrared imaging spectroscopic survey.

• Polymer(Korea)
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• v.39 no.1
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• pp.56-63
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• 2015

The object of this study is to prepare microcapsules containing a diisocyanate compound, apply them to self-healing protective coating, and evaluate the self-healing capability of the coating by atmospheric moisture. Isophorone diisocyanate (IPDI) polymerized under humid atmosphere, indicating that IPDI can be used as a healing agent. Microencapsulations of IPDI were conducted via interfacial polymerization of a polyurethane prepolymer with diol compounds. The formation of microcapsules was confirmed by Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The mean diameter, size distribution, morphology and shell wall thickness of microcapsules were investigated by optical microscopy and scanning electron microscopy (SEM). The properties of microcapsules were studied by varying agitation rates and diol structure. The self-healing coatings were prepared on test pieces of CRC board. When scratch was generated in the coatings, the core material flew out of the microcapsules and filled the scratch. The self-healing coatings were damaged and healed under atmosphere with 68~89% relative humidity for 48 h, and SEM and impermeability test for the specimens showed that the scratch could be healed by atmospheric moisture.