• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.284-293
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• 2022

After extracting the calcium component from the KR slag and the converter slag using ammonium chloride solution, the extract was reacted with carbon dioxide to synthesize precipitated calcium carbonate (PCC). In order to understand the effect of ultrasonic waves on calcium extraction from slags and calcium carbonate synthesis, the efficiency of calcium carbonate synthesis according to the with or without of ultrasonic waves was analyzed. The synthetic efficiency of PCC was investigated according to various experimental conditions, and the synthesized calcium carbonate was analyzed using XRD and SEM. In both slags, the amount of PCC decreased as the reaction temperature increased. The pH at the end of the experiment capable of synthesizing the maximum PCC in the carbonation reaction was 7 (irradiated with ultrasound) and 8 (irradiated without ultrasound), respectively. Because the pH of the extraction filtrate is different when irradiated with or without ultrasound, the pH was adjusted to 9 by injecting an additive (10 M NaOH) before the carbonation experiment, and then the experiment was performed. When calcium was extracted from KR slag, the crystal phase appeared as calcite regardless of the pH at the end of the experiment. However, when calcium was extracted from the converter slag and the pH was set to 7 at the end of the experiment, the crystal phase of PCC appeared as a mixture of calcite and vaterite.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.1
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• pp.101-110
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• 2022

For this purpose, the authors proposed and proved usefulness of the modified mean skin temperature which is integrated mean radiation temperature and the effect of floor contacted heat conduction. The mean radiation temperature is applied form factor between half cross-legged human body and surrounding wall of indoor. In addition the floor contacted heat conduction is applied heat transfer coefficient of half cross-legged human body. Eight Korean young men were targeted for the experiment. From the experiment the authors excerpted physiological reaction and psychological reaction in Ondol environment which is combined physiccal environmental factor of artificial climate chamber, air and floor temperature. As a result of the experiment it is confirmed that heat conduction has more impact than heat exchange from existing research for the heat exchange between half cross-legged human body and surrounding wall in Ondol thermal environment. Thereby, it is proved the effectiveness of the modified mean skin temperature which is added floor contacted temperature to the Ondol thermal environmental evaluation index.

• YAKHAK HOEJI
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• v.18 no.2
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• pp.161-164
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• 1974

m-Hydroxyaniline was reported to be converted to m-methoxyaniline with dimethylsulfate. However, while repeating the experiment with the same reaction condition, it was learned that the reaction product was not m-methoxyaniline but m-methoxy dimethylaniline. It was confirmed with nmr and ir spectrum and the comparison of bp and mp of the derivatives. Elemental analyses of the derivatives were also consistant with the fact N-dimethylation along with O-methylation occurred.

• Journal of Korea Foundry Society
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• v.5 no.4
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• pp.271-282
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• 1985

In order to investigate the mold reaction characteristics of Mn steel and Cr steel castings individually, the mold reaction products were examined by scanning electron microscopy, electron prove microanalyzer and X-ray diffractometer. From this experiment, the results were summarized as follows: 1) The mold reaction depth increased with increase of Mn content, while it decreased with increase of Cr content. 2) Mold reaction depth decreased with Mn content at $1200^{\circ}C$. 3) Mn, among the reaction products, forms a low fusion silicate, Mn $O.SiO_2$ while Cr forms a stable oxide, $CrO_3$ which hindering the reaction between FeO and $SiO_2$ thus the formation of $FeO.SiO_2$ was depressed.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.1
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• pp.33-39
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• 2023

In this study, the effect of mixing condition of raw material powders possessing various particle size and particle size distribution on thermite reaction efficiency was investigated. When fine raw powders are used, rather the reaction yield tends to decrease due to agglomeration. In contrast, coarse raw powders make deteriorate the contact area between raw material powders containing Al reducing agent. To ensure the optimal thermite reaction efficiency, it is required to optimize a mixture condition of raw material powders prior to thermite reaction. From the current experiment, the maximum thermite reaction efficiency is 77%, which came from Nb₂O₅ + NiO +Al mixtures with size distribution from 9.25 to 22.63 ㎛.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.87-90
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• 2006

The experimental study has been done for two kinds of pelletized RDFs to Investigate the carbonization effect to the chlorine concentrations, the heating value and the yield of Produced char in variable conditions of the carbonizing temperature and reaction time. One(RDF-1) is made of 100% wasted plastics and the other(RDF-2) is made of 60% wasted paper with 40% wasted plastics. The screw type carbonizer heated Indirectly by oil burner was used for the experiment and RDF feeding rate was 3kg/hr. The carbonizing temperature was 300, 350 400 and $45^{\circ}C$ and the reaction tine was 5, 10 and 15 minutes respectively. As the increase of carbonizing reaction time and temperature, the chlorine reduction rate was increased and oppositely the yield of char was decreased At the temperature of $400^{\circ}C$ and reaction time of 10 minutes the chlorine reduction rate was 60% and the char yield rate was 80% for the RDF-1 and those of RDF-2 were 80% and 75%, respectively. Additional activation experiment to the char produced from RDF-2 was done in the activation reactor by hot steam supply. As the increase of activation time the iodine number was increased. At the activation time of 20 minutes the iodine number was 552mg/g and the yield of activated carbon was 16%.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.417-421
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• 2006

In this study, colloidal Ag solution was spouted on the surface of the inorganic pigment using the hybridizer system and the spray nozzle. Then, the surface of the inorganic pigment was modified by titanium dioxide in order to possess antibacterial ability. Nano-sized colloidal Ag was made by using a seed sol method in this study. It was confirmed that the size of particle per unit weight becomes enlarged, as the addition of $AgNO_{3}$ increased, and as the time of reaction increased, in the manufacturing process of nano-sized colloidal Ag. The antibacterial measurement of the inorganic pigment showed that the growth of fungus was reduced as the reaction time increased. It was measured that the antibacterial activity was excellent at fixed time frame, after the antibacterial ability appeared in $5{\sim}7$ hours of the antibacterial inoculation experiment. The experiment of titanium dioxide's Photocatalyst effect showed $60{\sim}70%$ efficiency in about 80 minute reaction time of the dissolution results regarding measurements of benzene. It was shown that more than 90% of the dissolution efficiency was achieved in the reaction time of about 30 minute.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.177-186
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• 2003

Today, human beings are faced with crisis of environmental pollution and fuel exhaustion because energy consumption has increased rapidly as a rise in population, therefore human beings are in need of hydrogen energy as a substitute energy. Hydrogen has the advantages of cleanness and boundlessness, but it has difficulties of storage and safety. Making a nameless hydrogen burner for household in consideration of hydrogen's peculiarity was tried. This hydrogen burner utilized the heat of reaction that was emitted when water was formed by reaction of hydrogen and oxygen, It was tried to impregnate Pt catalyst in ceramic fiber(substrate) for the reaction of hydrogen and oxygen to be reacted more easily. This experiment was inquired that hydrogen is appropriate for being used as burner fuel in home and found out whether its safe usefulness is possible or not.

• YAKHAK HOEJI
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• v.7 no.2_3
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• pp.51-54
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• 1963

In this experiment, it is found that the decomposition reaction of hexamine aqueous solution by heat is the pseudo first order reaction and the calculated decomposition velocity constants of Hexamine aqueous solution are 1.17 * $10^{-5}min.^{-1}(60{\deg}$ C), 1.99 * $10^{-5}min.^{-1}(70{\deg}$ C), 2.35 * $10^{-5}min.^{-1}(80{\deg}$ C), 6.63 * $10^{-5}min.^{-1}(100{\deg}$ C). In the result, the activation energy of decomposition reaction of hexamine aqueous solution is 12 $Cal.mole^{-1}$.

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.444-445
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• 2006