• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.71-75
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• 1986

The forming reaction processes of magnesium aluminate spinel by a thermal decomposition of sulfate hydrate were studied with DTA, TG. SEM and X-ray powder diffraction methods. The hydrous salt composed of the mixture of the two compounds of $MgSO_4$ $6H_2O$ and ${AL_2}({SO_4})_17H_2O_3$ in which both sulfates were crystalline. On heating the hydrous slat the crystalline magnesium and aluminum sulfate anhydride to amorphous alumina magnesium sulfate anhydride decomposed to amorphous magnesia and these amorphous oxides reacted completely each other to form a spinel at $1000^{\circ}C$ The apparent activation energy of forming reaction of spinel was 36.5 kcal/mole($900^{\circ}C$~$1000^{\circ}C$) The crystallite size of spinel obtained at $1000^{\circ}C$ after 1 h was 380$\AA$.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.916-924
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• 1990

The preparatin of the fine TiN powders by reduction-nitridation of TiCl3-Al-N2 system was attempted in the temperature range from 350$^{\circ}$to 100$0^{\circ}C$. The formation mechanism and kinetics of TiN were examined, and the resultant TiN powder was characterized by means of XRD, PSA and SEM-EPMA methods. TiN was formed at temperatrue higher than $600^{\circ}C$. As an intermediate phase, AlTi was obtained. The apparent activation energy for the formation of TiN was approximately 4.2kcal/mole(600$^{\circ}$~90$0^{\circ}C$). The crystallite size and lattice constnat of TiN powder obtained in the temperature range from 600$^{\circ}$to 100$0^{\circ}C$ for 2h at the Al/TiCl3 molar ratio of 1.0 were 160~255A and 4.231~4.239A, respectively. According to PSA measurement, the mean particle size ranged from 14.0 to 14.8${\mu}{\textrm}{m}$.

• Journal of the Korean Society of Safety
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• v.6 no.4
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• pp.66-72
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• 1991

Spontaneous ignition characteristics were observed by performing experiments for granulated activated carbon at constant ambient temperature in an oven. As the results of the experiments, the critical spontaneous ignition temperature of sample for large, intermediate and small vessels was 158.5$^{\circ}C$ , 165.5$^{\circ}C$ and 174.5$^{\circ}C$, respectively. It was found that the critical spontaneous ignition temperature decreased and the ignition induction time increased as the sample vessel size increased. Apparent activation energy of the sample calculated from the Frank= kamenetskii's thermal ignition theory was 17.81＊10$^3$J/mol.

• KSBB Journal
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• v.6 no.1
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• pp.99-103
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• 1991

The optimum conditions and rates of absorption of isobutylene in aqueous para-toluene sulfonic acid(PTSA) were studied experimentally in a stirred reactor. The effects of acid concentration(30-70 wt%), acid loading (0.3-5), mixing intensity(400-1000 rpm), and temperature ($20-80^{\circ}C$) on the absorption conditions were examined. The absorption rate of isobutylene was first order in isobutylene and variable order in PTSA concentrations. The apparent energy of activation was found to be 13 Kcal/mole.

• Textile Coloration and Finishing
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• v.9 no.5
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• pp.10-18
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• 1997

In order to study the properties of safflower yellow colors, thermodynamic parameters and dyeing properties on the silk in several dyeing conditions were investigated. The uv-visible spectra of safflower yellow colors in several solvents show hypsochromic shift with the polarity of solvent but bathochromic shift with increasing acidity of solution. The apparent diffusion coefficients and standard affinities of dyeing increased with the increase of dyeing temperature. The standard heat of dyeing(${\Delta}H^0$), entropy change(${\Delta}S^0$) and activation energy($E_{act}$) were calculated to be - 1.144kcal/mol, -7.498(5$0^{\circ}C$)~-3.804(9$0^{\circ}C$)cal/molㆍdeg and 0.123kcal/mol, respectively. The concentration of safflower yellow colors in the silk fiber increased with dyeing temperature, time, concentration of colors and acidity of initial dyebath. Silk fabrics were dyed bright yellow by pre-mordanting with tin chloride. Lightfastness of silk fabrics pre-mordanted by tin chloride was not excellent.

• Textile Coloration and Finishing
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• v.11 no.4
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• pp.39-49
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• 1999

In order to study the properties of cochineal colors, uv-visible spectra of cochineal colors solution, dyeing properties on the wool in several dyeing conditions and thermodynamic parameters were investigated. UV-visible spectra of cochineal colors solution showed hypochromic effect with the lapse of irradiation time but bathochromic shift with decreasing acidity of solution and addition of metallic ions. The concentration of cochineal colors in wool fiber increased with the increase of dyeing temperature, time, and acidity of initial dyebath. The value of apparent diffusion coefficients and standard affinities of dyeing decreased with the increase of dyeing temperature. The standard heats of dyeing$(\Delta{H}^\circ)$ and variation of entropy$(\Delta{S}^\circ)$ increased with the increase of concentration of initial dyebath. The activation energy$(E_a)$ were calculated to be 1.399~2.595kcal/mol in condition of 6~1%(o.w.f) dyebath. Wool fabrics were dyed reddish blue by iron sulfate, copper sulfate, aluminum acetate and tannic acid, and red by tin chloride, respectively. Lightfastness of wool fabrics dyed by cochineal colors were increased by mordant treatment, especially copper sulfate and iron sulfate treatment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.167-168
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• 2018

In this research, the feasibility of wireless senor for compressive strength evaluation was checked by applying on the actual apartment construction site with insulation formwork during winder period. As a result, there was no significant problem on monitoring the compressive strength of the concrete with the sensor. Thus it is considered that the suggested method can be an efficient method for the quality control at the construction site.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.169-170
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• 2018

The purpose of the research is suggesting the temperature compensation strength for Unicode of constructure standard from Ministry of land, infrastructure and transport. As a result, for the concrete mixture with 100 % OPC, 6, and 3 MPa of compensating strength values were necessary when the temperature were from 4 to 9℃, and from 9 to 17℃, respectively. Additionally, when the temperature was higher than 17℃, compensating strength value was not necessary. In the case of 20 % of blast furnace slag replaced concrete mixture, 9, 6, and 3 MPa of compensating strength values were necessary when the temperature were from 4 to 6℃, from 6 to 12℃, and higher than 17℃, respectively.

• Journal of the Korean Ceramic Society
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• v.26 no.4
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• pp.539-549
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• 1989

Polycrystalline TiO2 thin films were deposited on Si and Al2O3 substrates by CVD method. Ethyl titanate, Ti(OC2H5)4, was used as a source material for Ti and O, and Ar was used for carrier gas. In the surface chemical reaction controlled deposition condition, the apparent activation energy of 6.74 Kcal/mole was obtained, and the atomic adsorption on substrate surface was proved to be governed by Rideal-Elley mechanism. In the mass transfer controlled deposition condition, the deposition rate was in a good agreement with the result which was calculated by the simple boundary layer theory. It was also observed that TiO2 thin films show different surface morphology according to the different deposition mechanism, which was fixed by deposition conditions. This phenomenon could be well explained by the surface perturbation theory.

• Journal of the Korean Chemical Society
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• v.15 no.2
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• pp.85-93
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• 1971

Apparent molal valumes ${\phi}_v$ and relative viscosities ${\eta}_r$ of aqueous solutions of anilinium chloride have been determined at two degree intervals from 20 to $50^{\circ}C$ in the molar concentration range 0.003 < C < 0.4. The results are discussed in terms of partial molal volumes $\={V}^{\circ}$, deviations from the Debye-H$\''{u}$ckel limiting law, partial molal expansibilities $\={E}^{\circ}$, viscosity B coefficients calculated from the Jones-Dole equation, and energy of activation for viscous flow. In aqueous solution, anilinium chloride was found to be a weak structure-maker due to its hydrophobic group.