• Journal of Conservation Science
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• v.18 s.18
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• pp.5-18
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• 2006

Dujeong-dong site of Cheonan is known as the site of Baekje period in the first half of the fourth century. This study investigated the visible properties and the chemical composition of the 18 pieces of the glass found in the site, and considered scientific properties and periodic interrelationship of the glass on the basis of the analysis result. The observation of the visible properties and microstructure of ancient glass was performed with both an electron microscope and an optical microscope, and the chemical composition was conducted by way of both quantitative and qualitative analysis using Scanning Electron Microscope(SEM) with Energy Dispersive Spectrometer(EDS). In the analysis result, various chemical composition systems are identified in the glass beads of Dujeong-dong site, such as lead-barium, soda and potash glass, and also different shapes were found such as gold foil glass beads, tubular beads, and round beads. It is estimated that the classification of glass by means of its chemical composition was also closely related to the color of glass.

• Journal of Conservation Science
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• v.16 s.16
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• pp.104-109
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• 2004

The characteristics and composition of the ancient glasses excavated at Songdong-ri, Sangju, Kyongsangbuk-do were analyzed using Scanning Electron Microscope attached with Energy Dispersive Spectrometer. As the results, the glass beads of Songdong-ri showed that there were changed the composition, the color and types according to the periods. There were appeared potash and soda glass group at A.D.4 century and potash and mixed alkali glass group at A.D. 17 century. The potash glasses of A.D. 4c. were colored blue and contained low $Al_2O_3$ and CaO composition as below $5\%$. The soda glasses of This period were colored blue and red, and contained $Al_2O_3$ composition as upper $5\%$. But the potash glasses of A.D.17c. showed the transparent yellow color and considerably higher CaO, $11.7\%$. 'Coil glasses' typed unique were colored yellow-brown, Cu-blue and colorless, were classified the mixed alkali glass as upper $5\%\;of\;Na_2O\;and\;K_2O$. The composition of coil glasses were presented first at this study.

• Journal of Conservation Science
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• v.34 no.2
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• pp.119-128
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• 2018

This study revealed the material composition and characteristics of 19 glass fragments excavated from stone chamber No. 1 of Jeongchon Tomb in Naju through chemical composition analyses and observations. These characteristics were compared with the characteristics of the glass fragments excavated from No. 3 tomb of Bogam-ri in Naju. The purpose of this study was to identify the characteristics of the ancient glass of the Mahan-Baekje period. The glass fragments excavated from the Jeongchon Tombs can be classified into purplish blue, light-purplish blue, greenish blue, green, and mixture of purple blue and purple, based on their color. These beads were made using a drawn and casting technique. In addition, blue glass fragments were primarily excavated form No. 3 tomb of Bogam-ri. However, red glass fragments were not excavated from either of the tombs. According to chemical composition analyses, soda glass group and potash glass group were common in both the tombs. Additionally, alkali mixed glass group and lead barium glass group were excavated from Jeongchon Tombs and No. 3 tomb of Bogam-ri, respectively. The glass fragments excavated from No. 3 tomb of Bogam-ri have more color variations than those excavated from Jeongchon Tombs.

• Elastomers and Composites
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• v.46 no.4
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• pp.277-283
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• 2011

In this study, engineering grade and high intensity reflective sheets were prepared with glass beads and their reflection performance and physical properties were investigated. The reflective sheets prepared by using glass beads are divided into enclosed or encapsulated lens type, depending on whether the glass beads are open in air or not. Because of an extra layer on the glass bead surface, the enclosed lens type reflective sheets show very little change in the properties by bad weather conditions, compared to encapsulated lens type reflective sheets. Optimization of the amount of glass beads on the surface was carried out, which determines the retroreflective properties. Enclosed and encapsulated lens type reflective sheets with various colors were prepared and their coefficients of retroreflection were determined. The encapsulated type reflective sheet with white color shows a coefficient of retroreflection of $210.4cd/1x{\cdot}m^2$, which is higher than the enclosed type ($74cd/1x{\cdot}m^2$). Effect of washing on the reflective property and adhesive power of the reflective sheets was investigated, and it is found that the number of glass beads decreased with washing and the aluminum layer deposited was damaged extensively in the encapsulated lens type reflective sheets.

• Journal of Conservation Science
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• v.28 no.3
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• pp.205-216
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• 2012

65 samples of glass bead excavated from Mahan tombs of Asan Bakjimeure site consists of 13 of potash glass group and 52 of soda glass group and soda glass is superior in numbers. When classified according to color, purple blue glass bead is accompanied potash and soda glass group whereas purple glass bead is potash glass group and red, greenish blue, green and gold foil glass bead is soda glass group. Purple blue glass bead is classified as LCA type in which the content of the stabilizer is low. Of this, the soda glass categorized as LMK type with low content of MgO and $K_2O$ is determined that natron is used as the raw material. As to red glass, the homogeneous glass is LCA-B/HMK type and the heterogeneous glass is HCLA/LMK type. Thus, each of these two types are likely to be used plant ash and natron respectively. Greenish blue and green glass depends of the type that round glass is LCA-A/LMHK type and the segmented glass is LCA-B/HMK type. The gold foil glass bead is manufactured by the purity of 19.9~22.6K gold foil and the soda glass of HCLA/LMK type. In other words, the most of the glass bead of Asan Bakjimeure site is similar to the composition of the glass confirmed in other sites of the Baekche period. On the other hand, the greenish blue and green segmented bead and some red round bead is a different chemical composition is considered that the difference in raw materials. These characteristics is expected to be an important evidence for the understanding of the trade system of the ancient glass.

• Journal of Conservation Science
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• v.31 no.3
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• pp.255-265
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• 2015

In this study, the potash glass beads of 281 samples in 30 sites analyzed until now were classified according to the chemical composition. And the color, size, manufacturing technique and distribution period were compared. Korea potash glass beads are divided into 3 types depending on the stabilizer content. I, II type is the CaO and $Al_2O_3$ content of less than 5%. Relatively, I type has a high CaO and II type has a high $Al_2O_3$. In contrast, III type comprises more than CaO 5%. I, II type is the saltpetre, III type is estimated using plant ash as row material of flux. A review of the properties by type, I type is cobalt blue, copper blue and purple beads. The outer diameter is sized to the range 1.4~7.4mm. Also it was produced by the drawing technique. It was used continuously from BC 1C until around AD 6C. On the other hand, II type is outer diameter of 1.9~3.6mm and a copper blue beads. manufacturing technique is the same as the I type. This seems to have been in use since around AD 1C to 4C. Finally, III type is brown, colorless, amber beads and an outer diameter of about 10mm. It was formed by winding technique and appeared in the tombs of Goryeo and Joseon Dynasty. As a result, 3 types of potash glass beads distributed in Korea is likely to flowing through the various trade routes from different provenances.

• Journal of Conservation Science
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• v.23
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• pp.25-37
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• 2008

This study focuses on identification of mineralogical and geochemical characteristics and interpretation of raw material sources for prehistoric chlorite beads excavated from Geoseokri site in Boseong and Buntori site in Haenam, Korea. These prehistoric beads consist of three grayish blue ring-shaped beads, one dark green tubular bead and one greenish black tubular bead that show acicular-columnar and fibrous microtexture. The beads are composed of $SiO_2$, $Al_2O_3$, MgO and FeO as majors and a trace amount of $K_2O$, CaO and Na_2O$. Mineral species is mostly chlorite with a small amount of quartz and feldspar. Quantitative analysis indicates that the grayish blue ring-shaped beads and the dark green tubular bead belong to clinochlore and the greenish black tubular bead does to the boundary between clinochlore and sheridantie. Chlorite is a hydrous phyllosilicate mineral and it shows various microtexture of acicular, sheeted, earthy, granular andfibrous shapes. As its hardness is 2, chlorite is easily engraved due to its softness. It has aesthetic worthy as it shows green, black and greenish gray colors and pearly to greasy luster as well. These factors would lead to the extensive use of chloritic beads as ornaments from prehistoric times. Though the mineral sources of the chlorite beads can be found in central western region of Chungnam and Iwon of Hamnam, those areas are too distant from the two relic sites. Instead, chlorite ores commonly occur as altered products in wall rock alteration zone of every hydrothermal deposit. Therefore, it is probable that raw materials of chlorite were supplied from neighboring hydrothermal environment rather than far deposits. The result needs further study to verify raw material provenance interpretation, supply, manufacture and distribution on the basis of archaeological points of view.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.765-773
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• 2000

The degradation of humic acid using $TiO_2$ coatings was studied, $TiO_2$ coatings were prepared by dip-coating method. Sol solutions for coating were prepared by mixing the gel, which can be produced by the reaction of $TiOCl_2$ and $NH_4OH$ solution, and hydrogen peroxide solution, and hydrolysis of titanium tetraisopropoxide (TTIP). It was shown from XRD that coatings from sol aged at $100^{\circ}C$ for 18h with titanium peroxo solution were crystallized to anatase in the range of temperatures of $25^{\circ}C$ to $500^{\circ}C$. In contrast, those coated from TTIP were crystallized to anatase at temperature above $400^{\circ}C$. So the sols originated from $TiCl_4$ can be applied for not only on the heat-resistance substrates but on the plastic substrates. Thickness and the quality of the films were dependent on the withdrawing speed, the concentration of sol, and the number of coating. The films showed various interference colors depending on the thickness of them. In the case that the films coated 2 times at withdrawing speed of 2.5cm per minute by 0.2M sol, the films had a transparent light blue color with thickness of around 50nm. It was known from the result of photo-degradation by $TiO_2$ coatings using humic acid that the removal efficiency of $COD_{cr}$ was over 85% after illumination of $UV/H_2O_2$ for 40min. and that of UV/VIS absorbable materials was over 95%.