• Resources Recycling
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• v.1 no.1
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• pp.69-77
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• 1992

In this study, a talc flotation was fundamentally carried out with dolomite origin talc ore produced in Dong Yang Talc Mine at Chung-Ju. This ores are mainly composed with talc as a valuable mineral, dolomite as a gangue mineral and other minor minerals of hornblende, tremolite, actinolite, chlorite, calcite, epidote and iron oxide. In order to obtain some of fundamental data for the talc flotation from low grade dolomitic talc tailings which were abandoned -25mm +17 mm size, after the treatment of crude talc ores by screening and hand -picking at the mine, flotation characteristics of the pure talc and dolomite in this ores were first investigated by measuring floatability of the minerals at some experiment conditions. Furthermore, Several times of batch flotations for talc were performed experimentally to recover talc from the low grade dolomitic talc tailings. From the results obtained in this experiment, the conclusions can be summarized as follows ; 1) In the flotation of pure talc, the use of Dowfroth 250 as frother was the most effective in various kinds of frother and the proper addition amount was about 50 mg/${\ulcorner}$(200g/t) at the condition of this experiment. 2) In the flotation of pure talc, the use of kerosene as collector was not adequate, at the addition over 50mg/l of Dowfroth 250. 3) The adequate pH of pulp ranged from pH6 to pH9 in the talc flotation using Dowfroth 250 as frother. 4) The use of Quebracho as depressant for dolomite was not adequate for the recovery of talc, and more selective depressant was required. 5) In the talc flotation on D sample(dolomitic talc tailing), the suitable number of cleaning time was about 3. 6) At this experimental conditions for the talc flotation on D sample, the talc flotation concentrates of 1. 40% CaO and 84.5 whiteness could be recovered with the talc recovery of about 53%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.167-173
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• 2008

Pearlescent pigments have been widely used in cosmetic applications. Up to date; the most widely used pearl effect pigment is the mica-based pigment, which uses natural mica as the substrate that is in turn coated with metal of oxide interference layer. However, when natural mica is employed as a base material the final product often has a yellowish color, mainly due to the fact that natural mica contains low levels of iron as an impurity[1,2]. This study was focused on developing a pearl pigment which might have a similar sparkling effect as snow. This effect was found to be due to its structure and purity, and this concept was also applied to development of our pearl pigments. More specifically, this invented pearl effect pigments are the mixture of glass-flake and glass-flake coated metal oxides and present the optical properties of snow matrix such as refractive index and particle size, unlike only the glass-flake or glass-flake coated metal oxides to be applied in. Using base material having similar physical properties (refractive index and particle size) as snow matrix as platelet for pearl effect pigments, these invented pigments present a three-dimensional glittering effect of the snow matrix. With this invented figments an applied; we achieved the beauty of snow crystal from makeup products containing these pigments.

• Journal of Conservation Science
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• v.37 no.5
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• pp.606-616
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• 2021

From the collection of the National Kimhae Museum, qualitative analyses using microscopic observation, SEM-EDS, Raman spectroscopy, FT-IR-ATR spectroscopy, and GC-MS were conducted on three burnished red potteries-Jeoksaekmaoyeonwa burnished red pottery (Neolithic age red pottery), Dandomaoyeonwan burnished red pottery(Bronze age red pottery) and Jeoksaekmaoyeongajimun burnished red pottery(Bronze age red pottery)-to investigate the components of the red pigments and the binder. After the layers of the primer were separated from the red surface, crystals of red pigment particles and minerals were found on the red surface. Through SEM-EDS, Raman estimates that the red pigment is Among soil pigments with iron oxide(Fe₂O₃) as the main color development source, Red Ocher(Fe₂O₃). A band characteristic of the Urushiol polymer was detected in the FTIR-ATRspectra(4000~600cm^-1), GC-MS analysis confirmed the presence of the benzenemethanol-2-prophenyl, 4-heptylphenol, 1-tetracecanol, heptafluorobutyric texidecane, all of which are the ingredients of the directional structure of the lacquer present in the red layer. Therefore, it seemed that the three burnished red pottery: Jeoksaekmaoyeonwan pottery(Neolithic age burnished red pottery), Dandomaoyeonwan pottery(bronze age burnished red pottery) and the Jeoksaekmaoyeongajimun pottery(bronze age burnished red pottery) made by mixing minerals and Red Ocher(Fe₂O₃), with lacquer.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.48-67
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• 2013

This study was focused on the recognition of historical values and the establishment of conservation schemes for a Silla stone monument in Bongpyeong-ri, Uljin by combining the humanistic investigation of inscription reinterpretation and the scientific conservational diagnosis of deterioration. According to the investigation of inscription, a total of 13 letters were reconsidered compared to the preceding researches. Thus, the meaning and interpretation of previous inscription was partially changed. This monument is composed of gneissose leucogranite and the most suitable site as provenance of the stone would be the Jukbyeon seashore (2.1km). The site shows similar color, size and composition of minerals, gneissose structure and magnetic susceptibility as the Bongpyeong stone monument. This monument developed a structural crack (crack index 0.4) and a microcrack (crack index 2.0) along the gneissose structure. The horizontal strength is weaker than the vertical strength. Therefore, the cracks should be reinforced and treated. However, consolidating is not urgently needed because the total weathering grade by ultrasonic velocity shows the stage of moderate weathering(3,403m/s, 0.32). Also, the major problems of chemical deterioration are blackening (85.2%) with soil, iron oxide,rubbing mark, and salt crystals (17.3%) from the sea. Therefore, the contaminants and the salt crystals should be removed using pressure spray and pulp paper, while the application of poultice should be examined through clinical tests.

• Conservation Science in Museum
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• v.25
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• pp.63-84
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• 2021

In order to investigate the diverse physicochemical changes that occurred in traditional Korean pottery during its production, including before and after firing, this study produced six replicas of a celadon maebyeong inlaid with cloud-and-crane designs, respectively corresponding to the process of shaping, carving, inlaying designs, first firing, glazing and second firing, respectively. It then conducted a scientific study of these six replicas and analyzed their images through high-resolution three-dimensional transmission imaging. The materials used for the replicas show different mineral phases and even colors depending on the components of each material. For example, black inlay with a high content of iron oxide (Fe₂O₃) shows dark colors and white inlay with a high alumina (Al₂O₃) content appears white. Physicochemical properties such as chromaticity and magnetic susceptibility and major components of the replicas were confirmed by the differences in the density in the computed tomography (CT) images. The characteristics of fired products such as fine structure, absorption ratio, apparent porosity, and other characteristics of the major mineral components were identified by the presence of pores and the formation of cracks inside the replicas in the image analysis.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.226-231
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• 2020

Polyvinyl pyrrolidone nanofibers including nickel, zinc, and iron precursors were fabricated via the electrospinning method. To convert as-spun nanofibers to Ni0.5Zn0.5Fe2O4 oxide nanof ibers which is capable of shielding an electromagnetic wave, heat treatment conditions were optimized. To obtain the heat treatment condition that can exclude amorphous carbon black and secondary crystal phase, samples were taken at each temperature while the calcination process and analyzed. According to the X-ray diffraction (XRD) analysis, the Ni0.5Zn0.5Fe2O4 crystal phase started to appear from 300℃, but it was confirmed through energy dispersive spectroscopy (EDS) analysis that heat treatment of 500℃ or more was required to remove most of the carbon black. When the calcination temperature exceeds 650℃, crystal nuclei starts to grow and the fiber surface condition becomes rough, so it was confirmed that the heat treatment conditions should be selectively determined according to the application field.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.41-48
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• 2021

Formulations which are dispersed in water are often used in color cosmetics because they are characterized by no powder flying, not sticky, and high adherence while giving a light feeling of use. However, little research has been considered on the effect of the pigment on the above formulations used in color cosmetics. In this study, experiments were conducted to measure and analyze the effect of pigments on the formulation of pigments, organic pigments, and pearl polish, which are mainly used in the manufacture of color cosmetics, on appearance changes, pH changes, and photometric stability. Carmine or ferric ferrocyanide coated titanium dioxide mica-based pigments were not suitable for use due to poor photostability, with colors appearing on the surface from low viscosity formulations. Organic pigments had a good photostability of 1% of the formulation which are dispersed in water, but were not suitable for use because they came out of color on the water surface and did not spread well due to the clumping of powders. The titanium dioxide mica system pigments coated with pearl polish, inorganic pigments, and iron oxide were suitable for use due to their excellent appearance and optical stability in the formulation. Furthermore, the pH of all samples distributed by each pigment seems to be within the range of 3.0 to 9.0, which is suitable for cosmetic applications. This is expected to help manufacture color cosmetics with a stable water dispersible formulations by selecting and using stable pigments in anticipation of the behavior of pigments in the formulations.

• Conservation Science in Museum
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• v.27
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• pp.67-90
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• 2022

A C-46 transport aircraft, which can be thought of as a large cultural heritage item from the modern period, was subjected to paint analysis and conservation treatment in preparation for its exhibition. The C-46 is the first aircraft ever dispatched to overseas combat zones by the Korean Air Force and carried out missions during the Vietnam War. The aircraft is mainly made of aluminum and shows signs of corrosion on its surface, including pitting and etching, as well as gray and white powdery attachments. In the analysis of the paint, diatomite(SiO₂·nH₂O) was confirmed in the red paint, titanium dioxide(TiO₂) was identified in the white paint, black iron oxide(Fe₃O₄) was detected in the black paint, and colcothar(Fe₃O₄) mixed with putty was confirmed in the blue paint. Infrared spectroscopy revealed the use of alkyd resin in the paint on the main body and nitrocellulose in the Taegeuk pattern. During the conservation treatment, mechanical cleaning, such as sanding, was conducted to remove paint and varnish from the surface. Corrosion was removed by sanding and cleaning with chemical solvents, and new paints and varnishes were applied. Through the paint analysis and conservation treatment, the aircraft was made available for exhibition in a stable condition.

• Journal of Conservation Science
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• v.37 no.2
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• pp.77-89
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• 2021

In this study, materials and color formation techniques were assessed for black potteries excavated from the Janghyeon-dong, Jungsan-dong and Gyodong-ri sites during the Proto-Three Kingdoms period in Ulsan, Korea. Although the black potteries were black superficially, the inner cores were either black or reddish yellow. Microscopy analysis identified that body clay was used for reddish iron oxide rich soils with quartz, alkali feldspar and mica, along with grains of myrmechite texture. Additionally, as marginal differences exist in the contents of SiO₂, Fe₂O₃ and CaO, the composition of the host rock and clay distributed around the sites was affected. Thus, we can deduce that pottery was made by soiling at a short distance. Raman spectroscopy results revealed that the black layer of the black pottery was used as amorphous combustion carbon. In addition, as a transparent layer of brown lacquer was observed on the substrate that was in contact with the surface layer, the black layer of the pottery induced black color development by a combination of combustion carbon and lacquer. Based on the mineral composition and microtexture of the body clay, the firing temperature of the potteries seemed to range from 750 to 850℃, whereas the lacquer layer was pyrolyzed at 468℃ by thermal analysis. Therefore, a combined layer of combustion carbon and lacquer, which formed the black color, was painted after the body clay was fired.

• BMB Reports
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• v.28 no.4
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• pp.293-300
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• 1995

The radical centers detected in the reaction of metmyoglobin (MetMb) with hydrogen peroxide ($H_2O_2$) have been studied by using a spin trapping technique. A broad 5-line asymmetric electron spin resonance (ESR) spectrum, with $2A_{max}=4.07\;mT$ and $2A_{min}=2.97\;mT$, obtained after incubation of MetMb with $H_2O_2$ in the presence of a spin trap, 5,5-dimethyl pyrroline-N-oxide (DMPO) was gradually weakened with time and disappeared completely by 6 min after addition of guanidine-HCl (14 M). When a higher concentration (6 M) of the agent was added, the signal disappeared within 40 see and the DMPO/OH signal appeared immediately. Then, a new 8-line signal with similar intensities grew gradually and was fixed by 45 min, coexisting with the DMPO/OH signal. This new signal was found to be composite, consisting of two different radical species. One of the 6-line signals, with $a_N$ 1.49 mT and $a_H$ 0.988 mT, was assigned to the DMPO/phenoxyl radical adduct. The second 6-line signal with $a_N$ 1.55 mT and $a_H$ 2.22 mT was assigned to carbon-centered radical adduct. When 3,3,5,5-tetramethylpyrrolin-N-oxide (TMPO), was employed in the place of DMPO, another broad asymmetric 5-line signal was detected with $2A_{max}=3.99\;mT$ and $2A_{min}=3.04\;mT$, which is virtually identical to that obtained from the DMPO system The shape of the spectrum of the TMPO adduct changed drastically, with lapse of time resulting in a broad singlet after 40 min. The broad singlet was assigned to the porphyrin radical adduct. Incubation of globin with Fenton reagent in the presence of DMPO initially gave a DMPO/OH signal. Then, a new 12-line signal began to grow after one minute and fixed after 15 min. coexisting with the DMPO/OH signal, This 12-line signal was assigned to DMPO/phenoxyl with $a_N$ 1.47 mT, $a_{{\beta}H}$ 0.99 mT and $a_{{\gamma}H}$ 0.13 mT. A minor concentration of carbon-centered radical adduct was also detected. This radical composition is identical to that of guanidine HCl treated MetMb/DMPO/$H_2O_2$ system, indicating that the radical producing conditions are somehow common in both systems. Heme iron can be released by excess $H_2O_2$ in the MetMb/$H_2O_2$ system, providing for Fenton reagent. When MetMb was pretreated with tyrosine blocking agent, $KI_3$ the broad 5.line MetMb-derived signal was not detected in the MetMb/DMPO/$H_2O_2$ system, whereas no such effect was detected on such system of Hb in which the radical center was assigned to cysteine residue not tyrosine, indicating that tyrosine residue is a main radical center produced in the MetMb/$H_2O_2$ system Thus, the present data strongly support the previous indication that the apomyoglobin-derived radical center formed in the reaction of MetMb with $H_2O_2$ is a tyrosine residue.