• 보존과학연구
• /
• s.31
• /
• pp.43-57
• /
• 2010

This study intends to provide quantitative data about the extraction characteristics of major elements of earthenware by executing soaking test of cleaning agents. It aims at providing basic data for the stability assessment when applying the cleaning agents for conserving earthenware. The data will be extracted from the analysis of co-relationship between the physical characteristics and the ion extraction characteristics. XRD analysis displayed that AT-1, AT-2 and AT-3 which did not generate mullite were fired at lower than 1,000 whereas AT-3 and AT-5 that included mullite were higher than 1,000. The degree of absorption was AT-4 > AT-2 > AT-1 > AT-3 > AT-5 in order and the correlation between the degree of absorption and firing temperature of earthenware displayed a positive correlation. Extraction amount of oxalic acid which was used for the removing iron oxide was AT-1 > AT-2 AT-4 > AT-3 > AT-5 in order. and the ion extraction data displayed that there is a positive correlation with absorption level. However AT-1 and AT-2 which were fired at lower temperature showed that there was no correlation between the ion extraction characteristics and absorption level. Ion extraction of citric acid produced little amount compared with the one of oxalic acid, yet it caused less damage to earthenware than oxalic acid when it applied. The result of ion extraction level in the absorption test displayed that Fe had higher level than in Si, Al from the test for both oxalic acid and citric acid. Based on the regression analysis of the data from the previous studies, the physical characteristics of the earthenware and ion extraction level, further studies will be conducted on the predicting technique on the extraction characteristics of major elements of earthenware samples for the conservation in future.

• Journal of the Korean Ceramic Society
• /
• v.42 no.4
• /
• pp.237-244
• /
• 2005

We prepared the cylindrical $\gamma-alumina$ pellets of 5 mm in diameter and 10 mm in average length using amorphous alumina and pore generating agent. The pellets were immersed in an aqueous solution of the mixture of $Fe(NO_{3})_{3}{\cdot}9H_{2}O$ and $CH_{3}COOH$. They were then hydrothermally treated at $200^{\circ}C$ for 3 h in autoclave, dried and calcined. For the application as an environmental catalyst, we investigated the decomposition characteristics of aniline and the initiation characteristics of $OH^{\cdot}$ conversion action in $O_{3}$ environment with or without the $Fe_{2}O_{3}$ supported y-alumina catalyst and $O_{3}$ molecule.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.130-131
• /
• 2013

Nanostructured oxides are widely used in heterogeneous catalysis where their catalytic properties are closely associated with the size and morphology at nanometer level. The effect of particle size has been well decumented in the past two decades, but the shape of the nanoparticles has rarely been concerned. Here we illustrate that the redox and acidic-basic properties of oxides are largely dependent on their shapes by taking $Co_3O_4$, $Fe_2O_3$, $CeO_2$ and $La_2O_3$ nanorods as typical examples. The catalytic activities of these rod-shaped oxides are mainly governed by the nature of the exposed crystal planes. For instance, the predominant presence of {110} planes which are rich in active $Co^{3+}$ on $Co_3O_4$ nanorods led to a much higher activity for CO oxidation than the nanoparticles that mainly exposed the {111} planes. The simultaneous exposure of iron and oxygen ions on the surface of $Fe_2O_3$ nanorods have significantly enhanced the adsorption and activation of NO and thereby promoted the efficiency of DeNOx process. Moreover, the exposed surface planes of these rod-shaped oxides mediated the reaction performance of the integrated metal-oxide catalysts. Au/$CeO_2$ catalysts exhibited outstanding stability under water-gas shift conditions owing to the strong bonding of gold particle on the $CeO_2$ nanorods where the formed gold-ceria interface was resistant towards sintering. Cu nanoparticles dispersed on $La_2O_3$ nanorods efficiently catalyzed transfer dehydrogenation of primary aliphatic alcohols based on the uniue role of the exposed {110} planes on the support. Morphology control at nanometer level allows preferential exposure of the catalytically active sites, providing a new stragegy for the design of highly efficient nanostructured catalysts.

• Journal of Conservation Science
• /
• v.34 no.4
• /
• pp.245-257
• /
• 2018

To investigate the deterioration of textiles with metal thread, I surveyed 40 textile objects, dating from the 11th to the 19th century from Korea, China, Japan, and Central Asia at the Metropolitan Museum of Art, New York. This survey included various types, widths, and thicknesses of metal thread. In addition, deterioration was examined under the microscope and color information was collected using the spectrophotometer. While investigating metal thread in the collections, I fabricated 12 different types of metal samples with metal leaf(24K gold, silver, and copper leaf), adhesive (hide animal glue and a mixture of hide animal glue and iron oxide red), and paper substrate(Korean mulberry and Taiwanese kozo paper). The accelerated deterioration process of those fabricated samples was carried out using a light box(UV and daylight), and a humidity cabinet. In the light experiment with blue scales textile fading card(aka, blue wool standard), the metal leaf began to peel off during the deterioration process with 756,000 lux-hours UV and daylight. In the temperature and humidity experiment, I could observe the reddish tarnish on copper, and some part of it began to peel off. Color reading on the light exposed samples showed that the degree of color change on the surface follows the amount of exposure as it increased over time. On the other hand, color change on the samples after artificial deterioration using temperature and humidity factors showed random change of color with occasional spikes. Distortion of original shape worsened in the samples exposed to temperature and humidity.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.3
• /
• pp.431-442
• /
• 2012

The purpose of this study, is to separate magnetic separation devices using permanent magnets by using magnetization characteristics remaining in treated water after adsorption and synthesizing phosphorus adsorbent capable of magnetic separation for efficient removal of phosphorus. The synthesis of the adsorbent which set Zirconium(Zr) having high friendly features for phosphorus as an element, and by synthesizing Iron Oxide($Fe_3O_4$, another name of $Fe_3O_4$ is magnetite) being able to grant magnetism to Zirconium Sulfate($Zr(SO_4)_2$), zirconium magnetic adsorbent(ZM) were manufactured. In order to consider the phosphorus adsorption characteristics of adsorbent ZM, batch adsorption experiment was performed, and based on the results, pH effect, adsorption isotherm, adsorption kinetics, and magnetic separation have been explore. As the experiment result, adsorbent ZM showed a tendency that the adsorption number was decreased rapidly at pH 13; however, it was showed a high amount of phosphorus removal in other range and it showed the highest amount of phosphorus removal in pH 6 of neutral range. In addtion, the Langmuir adsorption isotherm model is matched well, and D-R adsorption isotherm model is ranged 14.43kJ/mol indicating ion exchange mechanism. The result shown adsorption kinetics match well to the Pseudo-second-order kinetic model. The adsorbent ZM's capablility of regenerating NaOH and $H_2SO_4$, was high selectivity on the phosphorus without impacts on the other anions. The results of applying the treated water after adsorption of phosphorus to the magnetic separation device by using permanent magnets, shows that capture of the adsorbent by the magnetization filter was perfect. And they show the possibility of utilization on the phosphorus removal in water.

• Membrane Journal
• /
• v.14 no.2
• /
• pp.149-156
• /
• 2004

This work focused on the degradation of natural organic matter (NOM) present in lake water using a combined pkotocatalysisimicrofiltration (MF) process. The system performances were investigated in terms of organic removal efficiency and membrane permeability. The addition of iron oxide particles (IOP) into the photocatalytic membrane reactor improved initial NOM removal by sorption, but during photocatalysis the removal efficiency was reversed, probably due to the scattering of UV light by IOP. The modification of TiO$_2$ surfaces by IOP deposition was conducted to enhance the photocatalytic NOM removal efficiency. A minimal amount of Impregnation of IOP on TiO$_2$ surfaces was required to prevent the light scattering effect as well. The coating of MF membranes with IOP helped to improve the NOM removal efficiency while sorbing NOM by IOP. Regardless of tile operating conditions and particles addition examined, no significant fouling was occurring at a flux of 15 L/$m^2$-h during entire MF operation.

• Journal of the Mineralogical Society of Korea
• /
• v.24 no.1
• /
• pp.31-36
• /
• 2011

Meteorites are extraterrestrial solid rock fragments that fell from the outer space. Investigating mineral magnetic properties of the Meteorites is essential in understanding the evolution of planets and asteroids in the Solar System. In particular, magnetic characterization of magnetic mineral can provide constraints on the progress of differentiation in ancient planetary bodies. In the present study, ratio of thermoremanent magnetization (TRM) over saturation isothermal remanent magnetization (SIRM) was applied to diagnose the magnetic minerals in meteorites and igneous rocks. Distinctive classification of TRM/SIRM suggests that kamacite, tetrataenite, magnetite, and (Cr,Ti)-rich iron oxide are responsible for the magnetization of H5 Richardton, LL6 St. Severin, ALH84001, and DaG476, respectively. The TRM/SIRM ratio could be an efficient tool in identifying magnetic minerals especially when rocks or meteorites contain unstable material under heating.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.5
• /
• pp.1-5
• /
• 2010

This paper deals with a method to measure the thickness of scale-layer, iron oxide formed on the surface of the rolling steel, using a dielectric lens antenna. The dielectric lens antenna has an independent characteristic with the frequency in the X-band and changes the spherical wave radiated from a horn antenna into a plane wave at the focusing point. Using this concept, we regard a scale-layer on the rolling steel as a dielectric-PEC(Perfect Electric Conductor) layer and apply a theoretical analysis of the normal-incident plane wave. To reduce the phase error arising from the use of the dielectric lens antenna, this paper utilizes a regression process algorithm. In comparison with the conventional iteration algorithm, the present algorithm led to a unique solution for the thickness of the scale-layer.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.6
• /
• pp.505-513
• /
• 2008

The two-step thermochemical cycle was examined on the $CeO_2$, YSZ, and $ZrO_2$-supported $NiFe_2O_4$ to investigate the effects of support material addition. The supported $NiFe_2O_4$ was prepared by the aerial oxidation method. Thermal reduction was conducted at 1573K and 1523K while water-splitting was carried out at 1073K. Supporting $NiFe_2O_4$ on $CeO_2$, YSZ and $ZrO_2$ alleviated the high-temperature sintering of iron-oxide. As a result, the supported $NiFe_2O_4$ exhibited greater reactivity and repeatability in the water-splitting cycle as compared to the unsupported $NiFe_2O_4$. Especially, $ZrO_2$-supported $NiFe_2O_4$ showed better sintering inhibition effect than other supporting materials, but hydrogen production amount was decreased as cycle repeated. In case of $CeO_2$-supported $NiFe_2O_4$, improvement of hydrogen production was found when the thermal reduction was conducted at 1573K. It was deduced that redox reaction of $CeO_2$ activated above 1573K.

• Journal of Korean Society on Water Environment
• /
• v.22 no.6
• /
• pp.991-995
• /
• 2006

The layered double hydroxide with the insertion of chloride ions (LDH-Cl), which was synthesized by the co-precipitation method, was applied to investigate the fundamental aspects of the absorptive agent for phosphate removal from wastewater. The adsorption capacity was best described by the Langmuir-FreundIich isotherm, and the estimated isotherm parameters indicate that the LDH-CI capacity for the phosphate removal is much higher than that observed using a natural adsorbent material such iron oxide tailing. The kinetic experiment also showed that the LDH-Cl adsorption reaction rapidly at the adsorptive rate of 0.55 mg-P/g-LDH/min, implying that this adsorbent can be of use in the full-scale applications. The pH had a minimal effect on the LDH adsorption capacity in the range of 5 to 11, although the capacity dropped at the low pHs because of the change in LDH surface properties. Furthermore, other anions such as $Cl^-$ and $NO_3{^-}$ commonly found in the wastewater streams insignificantly affected the phosphate removal efficiencies, while $HCO_3{^-}$ ions had a negative effect on the LDH adsorption capacity due to its high selectivity. The phosphate removal experiment using the actual secondary effluent from a wastewater treatment plant showed the similar decrease in adsorption capacity, indicating that the bicarbonate ions in the wastewater were competing with phosphate for the adsorptive site in the surface of the LDH-Cl. Overall, the synthetic adsorbent material, LDH-Cl, can be a feasible alternative over other conventional chemical agents, since the LDH-Cl exhibits the high phosphate removal capacity with the low sensitivity to other environmental conditions.