• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.2
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• pp.143-152
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• 2005

Shotcrete for support of tunnel structures may contact with groundwater. The hazardous components in groundwater may cause corrosion of shotcrete. Also, the hazardous components may deteriorate the engineering properties of shotcrete, such as compressive strength, bond strength, flexural strength and so forth. The more the effect of the hazardous components on the shotcrete may increase, the more the stability of tunnel structure may decrease. The specimens were artificially immersed in various chemical solutions including hazardous components after the specimens were made at the tunnel construction site. It was performed to analyze the effect of the hazardous components in ground water on the engineering properties of shotcrete. The uniaxial compressive strength test, XRD, SEM were conducted to evaluate the durability and corrosion of shotcrete.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.648-658
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• 2015

Extraction of phytoncide oil from korea pine cone waste without damaging the pine cone tree itself was investigated using a steam distillation method. Also various components in the extracted phytoncide oil were separated using a column chromatography method. The extraction of phytoncide oil was effectively proceeded, and the maximum production yield of phytoncide oil could be obtained under $100^{\circ}C$ of distillation temperature and within 30 minute of distillation time. According to chemical analysis, it was found that the phytoncide oil from korea pine cone waste was consisted of more than 12 components such as ${\alpha}$-pinene, ${\beta}$-pinene, D-limonene, as main components. In addition, the aqueous hydrogel containing other components such as verbenone, ${\alpha}$-terpinieol, fenchol, different from components of phytoncide oil itself could be obtained through the steam distillation.

• Journal of Environmental Science International
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• v.28 no.1
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• pp.107-123
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• 2019

The aerosol chemical components in $PM_{2.5}$ in several regions (Seoul, Busan, Daejeon, and Jeju Island) were investigated with regard to their concentration characteristics and optical properties. The optical properties of the various aerosol components (e.g., water-soluble, insoluble, Black Carbon (BC), and sea-salt) were estimated using hourly and daily aerosol sampling data from the study area via a modeling approach. Overall, the water-soluble component was predominant over all other components in terms of concentration and impact on optical properties (except for the absorption coefficient of BC). The annual mean concentration and Aerosol Optical Ddepth (AOD) of the water-soluble component were highest in Seoul (at the Gwangjin site) ($26{\mu}g/m^3$ and 0.29 in 2013, respectively). Further, despite relatively moderate BC concentrations, the annual mean absorption coefficient of BC ($21.7Mm^{-1}$) was highest in Busan (at the Yeonsan site) in 2013, due to the strong light absorbing ability of BC. In addition, high AODs for the water-soluble component were observed most frequently in spring and/or winter at most of the study sites, while low values were noted in summer and/or early fall. The diurnal variation in the AOD of each component in Seoul (at the Gwangjin site) was slightly high in the morning and low in the afternoon during the study period; however, such distinctions were not apparent in Jeju Island (at the Aweol site), except for a slightly high AOD of the water-soluble component in the morning (08:00 LST). The monthly and diurnal differences in the AOD values for each component could be attributed to the differences in their mass concentrations and Relative Humidities (RH). In a sensitivity test, the AODs estimated under RH conditions of 80 and 90% were factors of 1.2 and 1.7 higher, respectively, than the values estimated using the observed RH.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E3
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• pp.87-94
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• 2005

Wet scavenging by rain drops is a most important removal process of air pollutants. In order to study the scavenging mechanisms of aerosol particles, the characteristics of chemical components in the rain water were examined as a function of the amount of rainfall. Rain water were collected continuously and separated into the soluble and insoluble components. The elemental concentrations in both components were determined by a PIXE analysis. The physical and chemical characteristics of atmospheric aerosols during the rainfall events were measured simultaneously. The elemental concentrations in rain water decreased substantially just after rain started and then gradually declined in subsequential rain fall exceeding 1.0 mm. The large particles were scavenged more easily than the fine particles. Fe, Ti and Si in rain water were in high insoluble state. Contrarily, almost whole of S was dissolved in rain water.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.302-304
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• 1997

Chemical structure and electrical properties such as water treeing and space charge accumulation of various raw materials(XLPE) used for power cable insulation were investigated. It was found that chemical structure was changed after crosslinking reaction and every materials have different amounts of DCP and antioxidant. Electrical properties were also changed after extraction using $CHCl_3$ and xylene. Water tree length was smaller with additives such as DCP and antioxidant and bigger with low molecular weight components of polyethylene than that of extracted samples. Heterocharge was changed into homocharge after extraction. This shows that additives and low molecular weight components of polyethylene cause the heterocharge.

• Journal of the Korean Chemical Society
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• v.22 no.2
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• pp.62-66
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• 1978

The polarizability tensor components for $NH_3,\;BH_3,\;HCN,\;C_2H_4,\;PO,\;PO^-$ and CO molecules are calculated by the variation method. The parallel components of the polarizability are closer to the experimental values than those of CNDO/2, MINDO/1 and MINDO/2, but the perpendicuar components of the polarizability are not closer to the experimental values than those of the other methods.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.1
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• pp.98-105
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• 1993

The chemical components of tobacco stalk, stems of tobacco caltivations, were analyzed and reconstituted tobacco sheet were made from the stalk and tobacco hyproducts by rolled and paper reconstitute tobacco sheet making process. The results were summarized as follow 1. In the viewpoint of chemical components, nicotine, total nitrogen and ash content of stalk were lower than those of stems, but crude fiber was two times higher than stems. 2. Reconstituted tobacco sheet of tobacco stalk blended were improved fragility and specific gravity than those of control. 3. Smoke components delivery of cigarette made from reconstituted tobacco sheet of tobacco stalk blended were similar to control cigarette. 4. According to the result of ranking preference test for control and sample cigarette, were not recognized significant at 5 percent level. 5. According to the result of areas test for control and sample cigarette, were not recognized significant at 5 percent level. 6. Optimum stalk blend ratio of reconstituted tobacco sheet manufacturing was from about 20 to 40% to the rolled sheet, and was from about 5 to 10% to the paper making process tobacco sheet.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.557-560
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• 2007

The metabolic discrimination of safflowers from various geographical origins was performed using 1H nuclear magnetic resonance (NMR) spectroscopy followed by principal components analysis. With a combination of these techniques, safflower samples from different origins could be discriminated using the first two principal components (PC) of the 1H NMR spectra of the 50% methanol fractions. PC1 and PC2 accounted cumulatively for 91.3% of the variation in all variables. The major peaks in the 1H NMR spectra that contributed to the discrimination were assigned to fatty acid (terminal CH3), lactic acid, acetic acid, choline derivatives, glycine, and safflower yellow derivatives. In this study, we suggest that various types of safflower can be discriminated using PCA and 1H NMR spectra.

• KSBB Journal
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• v.28 no.1
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• pp.31-35
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• 2013

In this work a $MABOOMS^{TM}$ has been employed to cultivate microorganisms and investigated the effects of culture medium components on cell growth. A 24-well microplate coated with 4-divided fluorescent sensing membranes was used to monitor the dissolved oxygen, pH and cell concentration during cultivations. Fluorescence intensity for dissolved oxygen or solution pH and reflectance for cell concentration was online monitored by using the $MABOOMS^{TM}$. The online monitoring results showed the effects of culture medium components on cell growth in cultivation processes very well.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1641-1643
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• 2009