• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1097-1100
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• 2001

In this paper, the electro-chemical-machining characteristics of Ni-Ti Shape Memory Alloy(SMA) was investigated. From the experimental results, the optimal electro chemical machining conditions for satisfying the machining quality(fine surface & high recovery stress) might be confirmed. And it was concluded that optical electro chemical condition for Ni-Ti SMA could be obtained at approximately 100% current efficiency and high frequency pulse current.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.25-33
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• 2023

This study analyzed the factors affecting the effectiveness of the Chemical Hazard Risk Management (CHARM). A survey was conducted on 104 learners who participated in the Risk Assessment training course at Occupational Safety and Health Training Institute. Through a self-administered questionnaire, the effect of personal characteristics, corporate characteristics, and safety and health level of the company on the effectiveness of chemical risk assessment was investigated. As a result of statistical analysis, the safety and health level of the company had a positive (+) effect on the effectiveness of Chemical Hazard Risk Management(CHARM), but personal characteristics and corporate characteristics had no relation to it. This study can be used as basic data for further research related to chemical risk assessment in workplaces.

• Journal of Environmental Health Sciences
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• v.44 no.6
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• pp.515-523
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• 2018

Objectives: Based on the results of a chemical substance emissions survey, we investigated characteristics of chemical emissions in industrial complexes and used them as basic data for chemical management. Methods: The emissions and characteristics of chemicals by major industrial complexes from 2011 to 2015 were analyzed using the Pollutant Release and Transfer Register homepage. To understand the status of chemical accidents for major chemicals emitted from the industrial complexes, the Chemistry Safety Clearing-house system of the National Institute of Chemical Safety was used. Results: Emissions from the top five industrial complexes accounted for about 30% of total chemical emissions. The chemical emission was the highest in the order of Ulsan Mipo Industrial Complex and Okpo Industrial Complex. The main chemicals emitted were xylene, ethylbenzene, ethyl acetate, toluene, dichloromethane, and others. Carcinogen emissions differed by industrial complex, but ethylbenzene and dichloromethane were the major chemicals for this type of emissions. Conclusion: Recently, the use and emission of chemicals have been continuously increasing. A chemical management plan should be prepared considering the characteristics of industrial complexes and chemical substance emissions.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1912-1914
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• 2005

The electrical, chemical and mechanical characteristics in transformer insulations are changed due to thermal stress. It is known that characteristics of transformer insulations is deteriorated such as decrease of dielectric strength, deterioration of dielectric constant and tensile strength of paper as transformer oil and paper are aged by thermal stress. Furthermore, chemical characteristics of them are deteriorated as like increment of moisture contents and dissolved by-products in oil, etc. In this paper we have been investigated chemical characteristics of transformer by accelerated thermal aging. For this working we have made experimental test cell and aged at a temperature up to $140^{\circ}C$ for 500 hours. The oil-paper insulation samples have been measured at intervals of 100 hours. For analysis we used Karl-Fisher titration method and high performance liquid chromatography (HPLC).

• Journal of the Korean Society of Tobacco Science
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• v.9 no.2
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• pp.3-9
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• 1987

This study was been conducted to determine chemical characteristics of soils in the major districts cultivating flue-cured tobacco plant. Also native soil productivities were measured by means of bioassay planting tobacco plant without fertilizer at 87 selected lolls through pot and field experiments. Inorganic nutrient in soils affecting the dry weight of tobacco leaves cultivated in the field were investigated. The results obtained are summarized as follows; 1. Among soil chemical characteristics, pH, $NO_3$-N, $NH_4$-N , $P_2O_5$, and Mg Influenced significantly the dry weight of tobacco loaves In pot experiment, whole In the field experiments, pH, $NO_3$-N, $NO_3$-N+$NH_4$-N, and Ca had influence. 2. Correlation coefficients between soil chemical characteristics and dry weight of tobacco leaves were higher in pot experiment than field. The results revealed that soil morphological characteristics might more close influence on dry weight of tobacco leaves than chemical characteristics. 3. For prediction of dry weight (Productivity) of tobacco leaves without fertilizer multiple regression analysis were introduced using troll chemical characteristics. A combination of pH, $NO_3$-N, and Ca was very reliable for prediction of productivity as equation. y=5.02+18.07$x_1$ +2.61$x_2$ +5.36$x_3$ R=0.444** Where $x_1$ : pH, $x_2$ : $NO_3$-N, $x_3$:Ca

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.85-89
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• 2007

This study was conducted to evaluate the prediction of sensory characteristics of smoke from the leaf chemical compounds and characterize leaf chemical components for the best tobacco taste's leaves in oriental tobacco. For analytical and sensory evaluations, seventy two grades were used. Sensory evaluation of tobacco smoke for six attributes were scored on fifteen-point scale by $10{\sim}14$ expert panels trained to estimate smoking quality quantitatively. The major leaf chemical compounds to predict the sensory characteristics of smoke were ether extract for tobacco-like, nicotine for impact and total nitrogen/nicotine ratio for irritation, and total sugar for off taste & odor. Within ${\pm}20%$ range of difference, the predictable probabilities of sensory characteristics of smoke from the leaf chemical compounds were 87.5 % for off taste & odor and $94.4{\sim}98.6\;%$ for tobacco-like, impact and irritation. As a result of K-means cluster analysis on the basis of tobacco taste, the desirable leaf chemical compound contents were $5.9{\sim}8.3\;%$ in ether extract, $1.35{\sim}2.27\;%$ in nicotine and $1.17{\sim}2.24$ in total nitrogen/nicotine ratio. This study suggest that the some regression equations may be useful to predict the sensory characteristics of tobacco smoke with a few selected leaf chemical compounds in oriental tobacco and to select the oriental tobacco leaves by means of enhancing the tobacco taste of cigarette.

• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.341-349
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• 2009

Natural grape extraction was extracted from grape component using diethyl ether as a solvent, and we tested various pharmaceutical and chemical characteristics of this extract. Characteristic experiments to use natural grape extract tested antimicrobial experiment using microbe in pharmaceutical material, and tested dye experiment using fiber in chemical material. From the result of characteristics experiment, some conclusions are obtained as follow. From the result of characteristics experiment, it obtained about 7.5%-grape extraction ratio as semi-solid state, and after dried in freezing from grape extract of semi-solid state, it obtained about 10%-grape extraction ratio as solid state of dark purple color. From result of antimicrobial experiment of grape extract, number of staphylococcus aureus (KCMC-01) and aspergillus niger (KCMC-02) in microbe decreased more and more according to time passage. This phenomenon showed that grape extract influences to antimicrobial effect. From the result of dye experiment of grape extract, it appeared in direction of dark purple color after dyed to use cotton and silk with fiber to control in pH 7.5. Specially the result which confirmed dye of fiber with optical electron microscope(OEM), we could know that it appears darker silk than cotton.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.955-958
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• 2000

In this paper, the electro-chemical-machining characteristics of Ni-Ti Shape Memory Alloy(SMA) was investigated. From the experimental results, the optimal electro chemical machining conditions for satisfying the machining quality(fine surface & high recovery stress)might be confirmed. And it was concluded that optical electro chemical condition for Ni-Ti SMA could be obtained at approximately 100% current efficiency and high frequency pulse current.

• Tribology and Lubricants
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• v.33 no.3
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• pp.106-111
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• 2017

Sapphire is an anisotropic material with excellent physical and chemical properties and is used as a substrate material in various fields such as LED (light emitting diode), power semiconductor, superconductor, sensor, and optical devices. Sapphire is processed into the final substrate through multi-wire saw, double-side lapping, heat treatment, diamond mechanical polishing, and chemical mechanical polishing. Among these, chemical mechanical polishing is the key process that determines the final surface quality of the substrate. Recent studies have reported that the material removal characteristics during chemical mechanical polishing changes according to the crystal orientations, however, detailed analysis of this phenomenon has not reported. In this work, we carried out chemical mechanical polishing of C(0001), R($1{\bar{1}}02$), and A($11{\bar{2}}0$) substrates with different sapphire crystal planes, and analyzed the effect of crystal orientation on the material removal characteristics and their correlations. We measured the material removal rate and frictional force to determine the material removal phenomenon, and performed nano-indentation to evaluate the material characteristics before and after the reaction. Our findings show that the material removal rate and frictional force depend on the crystal orientation, and the chemical reaction between the sapphire substrate and the slurry accelerates the material removal rate during chemical mechanical polishing.

• Korean Journal of Hazardous Materials
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• v.2 no.1
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• pp.1-5
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• 2014

Acidic chemicals like sulfuric acid, nitric acid and hydrogen chloride take up 37% of the total chemical accidents which took place for the past 10 years. When an acidic chemical leak happens, fume is generated, diffusing into the air, which might cause serious damage to health of local residents and the environment. However, we have only little reference data for production and using of acidic chemicals. In this study, we investigated characteristics of production and using for acidic chemicals with high accident frequency. As a results, domestic chemical accidents were categorized according to chemical types and production, using, and handling characteristics of acidic chemicals were identified. Sulfuric acid was handled in the largest amount, followed in the order of hydrogen chloride, nitric acid, acrylic acid, and hydrogen fluoride. Sulfuric acid is used in the industry of manufacturing composite fertilizer and mainly used for manufacturing fertilizer. Hydrogen chloride is used in the industry of manufacturing basic chemicals for petrochemical family and mainly used for pH regulator. It is expected that this results could be used as preliminary data for making decisions on facilities required intensive management in order to prevent chemical accidents and prepare countermeasures against such accidents.