• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.1291-1298
• /
• 2005

Shotcrete for the support of tunnel can contact with groundwater. The hazardous components in the groundwater cause the corrosion of shotcrete. Also, the hazardous components may deteriorate the engineering properties of shotcrete, such as compressive strength, bond strength, and flexural strength. The more the effect of the hazardous components on the shotcrete may increase, the more the stability of tunnel structure may decrease. It was analyzed to find the hazardous components in the ground water. The uniaxial compressive strength test, XRD, SEM were conducted to evaluate the durability and corrosion of shotcrete. These tests were performed on shotcrete specimens at 2, 4, 8, and 16 weeks. The specimens were immersed in various chemical solutions including hazardous components after the specimens were made at the construction site.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.2
• /
• pp.135-144
• /
• 2004

A total of 40 Korean and Japanese rice varieties were evaluated for their main chemical components, physical properties, cooking quality, pasting properties, and instrumental measurements. Based on their quality evaluations, it was concluded that Korean and Japanese rice varieties were not significantly different in the basic components of NIR (Near Infra Red) data and the chemical analysis from the uncooked brown and milled rices. Korean rice had a little bit higher protein and amylose contents but much lower fat acidity than those of Japanese rice from the chemical analysis. From all the data of three different kinds of NIR methods, Korean and Japanese milled rice were very similar except the taste score. Japanese rice showed a slightly higher taste score, a little bit higher lightness and whiteness, but lower yellowness and redness than Korean one. From all those data of NIR and the chemical analysis, Korean and Japanese rices had very similar components except the fat content.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.372-373
• /
• 2006

Chemical kinetics affects Cu CMP results (removal rate, Non uniformity etc.) Because Cu is removed by chemical action. Key factors in chemical kinetics are process temperature and concentration of slurry components. In this study, Hydrogen peroxide and citric acid were selected as a oxidant and a complexing agent and Slurry were made by mixing this components. In order to study effects of Chemical Kinetics, X-ray photoelectron spectroscopy (XPS) were performed on Cu sample after etching test as concentration of citric acid and slurry temperature. Finally Cu CMP was performed as same conditions.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.3 no.1
• /
• pp.11-16
• /
• 2005

Chemical mixtures of components, each of which are present at less than guidance concentrations, may be hazardous due to additivity, interactions, or both. Toxicological interactions may increase the health hazard above what would be expected from an assessment of each component singly, or all components additively. So chemical mixture are a particular issue in public health. There are several approach to assess whether there are additivity or interaction in assessing toxicological effects, such as, components-based approach, physiologically-based pharmacokinetic /pharmacodynamic(PBPK/PD) models, hazard index method, and weight-of evidence method. If we consider interaction or additivity effects in assessing the health effects of chemcial mixtures, we can get more accurate information about toxicological effects and dose-response relationship in chemical mixtures.

• Journal of Environmental Science International
• /
• v.6 no.5
• /
• pp.461-472
• /
• 1997

This study was carried out to investigate the characteristics of chemical components and precipitation at Kimhae area from March, 1992 to June, 1994. The pH values, concentration of soluble ions($Cl^-$, $NO_2^-}$ $NO_3^-}$, $NO_4^{2-}$-, $PO_4^{3-}$. $F^-$, $Mg^{2+}$, $Ca^{2+}$, $Mn^{2+}$, $K^+) and non-soluble metals(Cr.Si. Zn, Pb, Cu, Fe, Mn, Mg, Ad. V. Cal were measured by pH meter, IC (ion Chromatography) and ICP(Inductively Coupled Plasma). The data were analyzed by the dally. hourly distribution characteristics of acidity and chemical components, as well as the correlation between them. The results are as follows. 1. The pH range of precipitation was from 3.45 to 6.80 in Kimhae area. and average value was pH 4.62 and main chemical components were $SO_4^{2-}$, $Cl^-$, $NO_3^-$. The highest pH value and concentration appeared in initial rain, which might result from urbanlzation and industrialization in this area and long term transportation from China. 2. The hourly correction distribution of main anions related to pH value In the rainwater showed $SO_4^{2-}$ > $NO_3^-$ > $Cl^-$. Hourly concentration of heavy metal and each ion was highly correlated with pH in the precipitation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.35 no.2
• /
• pp.58-64
• /
• 2003

Because of its tendency of making strong Hoc on the fiber surface with fines, Meogujaengi has not been valued as a material of Hanji. As an attempt to manufacture high value-added products using the material made from Jumchihanji, this study performed morphological classification and chemical component analysis and selection of pulping of Meogujaengi method. As a result, it can be concluded as follows, 1. Meogujaengi is assumed to be a local variety of Broussonetia karinoki and its outward appearance is distinguished from Broussonetia kazinoki. 2. The bast fiber of Meogujaengi is longer and thinner than that of Broussonetia papyrifera or Broussonetia kazinoki. However, because of the coarse linear of fiber tissue, there are many clusters. 3. The cluster phenomenon of Meogujaengi is nothing to do with its chemical components. Although the contents of its chemical components are different from those of Broussonetia kazinoki, no component was found that obstructs pulping. 4. The pretreatment for suppressing the occurrence of clusters of Meogujaengi was effective, and it was necessary to do secondary beating using hollander beater after beating mixed with PAM using knife beater.

• Journal of the Korean Society of Tobacco Science
• /
• v.29 no.2
• /
• pp.80-84
• /
• 2007

This study was conducted to evaluate the prediction of sensory property of smoke from the leaf chemical property and characterize leaf chemical components for the best tobacco taste's leaves in burley tobacco. For analytical and sensory evaluations, sixteen grades were used. The major leaf chemical components to predict the sensory property of smoke were ether extract for tobacco-like, chloride for impact and total nitrogen/nicotine for irritation. Within ${\pm}20\;%$ range of difference, the predictable probabilities of sensory property of smoke from the leaf chemical properties were 100 % for tobacco-like, impact and irritation. As a result of K-means cluster analysis on the basis of tobacco taste, the desirable leaf chemical component contents were $6.5{\sim}6.8\;%$ in ether extract, $0.25{\sim}0.30\;%$ in chloride and $1.26{\sim}1.54$ in total nitrogen/nicotine ratio. This study suggest that the some regression equations may be useful to predict the sensory components of tobacco smoke from a few selected leaf chemical properties in burley tobacco and to select the burley tobacco leaves for enhance the tobacco taste of cigarette.

• Journal of Sericultural and Entomological Science
• /
• v.22 no.1
• /
• pp.52-58
• /
• 1980

Root system and distribution of soil components (pH, available P, K, Ca and Mg) were studied in a 20-year old, low-cutting mulberry field. The variety, kairyonezumigaeshi (Morus alba L.), was planted in a spacing of 1.8m${\times}$0.6m(740 tiess/10a). Roots and soil samples were taken from each of 196 blocks in a demension of 26${\times}$17${\times}$10cm(as shown in Fig. 1) from the soil between rows. 1. Whereas root system concentrated towards the stock, chemical components, pH, available P, Ca and Mg, were increasing toward the center of the row spacing. 2. Root system and distribution of chemical components between trees were not significantly different among blocks. 3. Roots were distributed most densely in a depth of 10∼20, intermediate 20∼30 and 30∼40, and least 0∼10cm. However, the concentrbtion of chemical components was the highest in a depth of 0∼10cm and decreased with soil depth. The soil. a depth of 0∼10cm on the center of row spacing, was the lowest in the root system and the richest in a chemical components. The results indicate that special fertilizinng management is required for the efficient absorption of nutrients.

• Korean Journal of Organic Agriculture
• /
• v.9 no.1
• /
• pp.29-36
• /
• 2001

This study was conducted to investigate the effects of microbial fertilizers on the yield of altari radish, chemical components of plant and soil, and the microbial floras. Six microbial fertilizers, MPK＋Husk＋Palma, Husk＋Palma, MPK＋Compost, Compost, Bio livestock cattle system (BLCS) cattle dropping, and Tomi, were used in this experiment. The yield of altari radish was increased in treatments of all microbial fertilizers. The concentration of all chemical components in plant were not significantly different. Whereas the amount of $P_2$$O_{5}$ in soil was increased in Compost treatment, the other components were not significantly different compared with control. The total bacteria and bacilli in soil were increased in Tomi, Husk＋Palma, and MPK＋Husk＋Palma treatments, and actinomycete and fungi were increased in Tomi treatment.

• Korean journal of food and cookery science
• /
• v.20 no.2
• /
• pp.219-226
• /
• 2004

This study was performed to investigate the change of chemical components and antioxidant activities in Hizikia fusiformis(Harvey) OKAMURA with blanching times. For chemical composition, the contents of minerals (K, Ca, Na, Mg, Fe, Cu, Mn and Zn), vitamins (vitamin C, ${\beta}$-carotene and ${\alpha}$-tocopherol) and total polyphenol were analyzed. The antioxidant activity was determined through free radicals (DPPH radical, superoxide anion radical, hydroxyl radical and hydrogen peroxide) scavenging activity and linoleic acid peroxidation inhibitory activity. As the blanching time increased, the contents of all minerals, vitamin C and total polyphenol decreased. However ${\beta}$-carotene and ${\beta}$-tocopherol were not affected by the blanching time. In addition antioxidant activities decreased with increasing blanching time.