• Korean journal of applied entomology
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• 제31권2호
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• pp.144-152
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• 1992

The juvenile hormone(JH) titers and juvenile hormone esterase (JHE) activities were mea¬sured in larval homogenates of the chestnut gall waL,J, Dryocosmus kuriphilus Yasumatsu, parasiting a susceptible and two resistant chestnut ( Cheuk-Pa, and Dan- Tak) varieties by GLC, Galleria wax test and Liquid scintilation counter. JH of the chestnut gall wasp was identified as JH- I. Their juvenile hormone titers were 35,800 GU/g(Cheuk-Pa), 30,900 GU/g (Dan-Tak), and 28,600 GU/g(susceptible variety). The juvenile hormone esterase activities were 1.48 n mole/min/ml(Cheuk-Pa), 1.63 n mole/min/ml(Dan- Tak), and 1.89 n mole/mini ml(susceptible variety). JH titer activity of the chestnut gall wasp parasiting resistant varie¬ties were higher than that from susceptible, whereas their JHE activity was higher in those from susceptible variety than those from resitant varieties. JH titer and JH specific esterase activity was inversely proportional.

• Journal of Conservation Science
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• 제36권5호
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• pp.393-404
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• 2020

We observed changes in the properties of the glaze layer according to the content of iron oxide and inferred the composition, content, and environment of the materials used in the past during the production process of black ware. First, experiments were conducted using different ratios of iron oxide, feldspar, calcite, and ash at different temperatures and firing environments; the characteristics of glaze were classified into five groups in the oxidation environment. Different properties were identified in the reducing environment above 1200℃. The crystal identified in the experiment was similar to the glaze characteristics in the excavated black ware. The crystal phase appeared in four groups: band shape, circular, arborescent phase, and needle crystal, depending on the change in the content of iron oxide. However, the difference in crystals did not appear significantly at high temperatures. In addition, crystals of glaze were divided into two groups depending on the component ratio. The presence or absence of feldspar is thought to affect crystallinity and amorphous iron oxide and the changes in the glaze layer changed substantially depending on the amount of iron oxide. In particular, it was confirmed that the aspects of iron oxide in the oxidation and reduction environments were different and, therefore, crystallization due to the firing environment also affected the optical characteristics.

• Journal of Conservation Science
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• 제26권3호
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• pp.213-228
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• 2010

The composition of Chinese ceramic shards has been the subject of analysis in Europe, beginning in the 18th century, and in China from the 1950s. Scientific studies of traditional Korean shards commenced in the United States and Germany in the 1980s, and studies within Korea began in the 1990s. From analysis of a large systematically collected dataset, the composition of porcelain produced during the Kory. dynasty, including 21 celadon and 10 whiteware groups, was characterized and compared with that of Chinese ceramics. The average composition of the body and glaze of several shards (usually three to five) from each group was determined, enabling comparisons between groups. The results show that the majority of groups were derived from mica-quartz porcelain stone, which was commonly used in Yuezhou, Jingdezhen, and other southern Chinese kilns. The composition of glazes includes clay and flux components; the latter were typically wood ash and limestone, initially as burnt but later as crushed forms. The earliest of the Kangjin glazes contained substantially less titanium oxide than did the Yuezhou glazes, which were typically formulated from body material and wood ash. The present study provides a comparative framework for the growing number of analytical investigations associated with excavations occurring in Korea.

• Journal of Conservation Science
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• 제6권1호
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• pp.3-14
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• 1997

Twelve Punchong sherds collected in Hakbongni, Kongju where the well known iron-painted on white slip were manufactured from late 15C to early 16C were analyzed for their composition and microstructure. The composition of the body was analyzed by X-ray fluorescence and that of glaze by electron probe micro-analyzer. Microstructure was observed by optical microscope, polarizing microscope, EPMA, and X-ray diffractometer. The results of composition of body and glaze of Hakbongni were compared with those of Punchong from Yongsuri, Boryong which was close to Hakbongni. The composition of body and glaze of these two areas were compared by principal component analysis using SPSS program. Hakbongni bodies have higher silica and flux materials but lower alumina and their glaze have higher silica, soda, iron oxide but lower alumina, calcia. Hakbongni punchong itself is divided into two groups. Their glaze is lime type. There are many remnant minerals, such as quartz, large feldspar mass with partially melted surrounding area, albite, biotite, and iron-oxide. From such a microstructure we can assume that preparation of raw material was rather crude and firing temperature quite low. Iron-painted material is identified as Mg/Fe/Al spinel by composition analysis and XRD pattern.

• Korean Journal of Agricultural and Forest Meteorology
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• 제18권4호
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• pp.253-263
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• 2016

Chrysanthemum production would benefit from crop growth simulations, which would support decision-making in crop management. Chrysanthemum is a typical short day plant of which floral initiation and development is sensitive to photoperiod. We developed a model to predict phenological development and leaf appearance of chrysanthemum (cv. Baekseon) using daylength (including civil twilight period), air temperature, and management options like light interruption and ethylene treatment as predictor variables. Chrysanthemum development stage (DVS) was divided into juvenile (DVS=1.0), juvenile to budding (DVS=1.33), and budding to flowering (DVS=2.0) phases for which different strategies and variables were used to predict the development toward the end of each phenophase. The juvenile phase was assumed to be completed at a certain leaf number which was estimated as 15.5 and increased by ethylene application to the mother plant before cutting and the transplanted plant after cutting. After juvenile phase, development rate (DVR) before budding and flowering were calculated from temperature and day length response functions, and budding and flowering were completed when the integrated DVR reached 1.33 and 2.0, respectively. In addition the model assumed that leaf appearance terminates just before budding. This model predicted budding date, flowering date, and leaf appearance with acceptable accuracy and precision not only for the calibration data set but also for the validation data set which are independent of the calibration data set.

• Journal of Digital Convergence
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• 제17권3호
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• pp.427-432
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• 2019

In the 12th century to the 13th century, was the heyday of celadon, Koryo celadon after experienced celadon firing technology of imitation to the peak period of the development of Chinese celadon, especially on decoration technology pioneered the self unique style, the way of engraving, $xi{\grave{a}}ngqi{\grave{a}}n$. During this period, the southern Song dynasty celadon in China also innovated in the mature celadon firing technology and became more distinctive. The decorative style also promoted the aesthetic interest of the Song dynasty. Celadon decoration is not only a decorative art of ceramic art, but also a representation of national cultural phenomenon with the traditional culture in the development of contemporary art, play a more important role and value.

• Conservation Science in Museum
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• 제29권
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• pp.65-80
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• 2023

This study investigated seven specimens of lead-glazed paving bricks in order to identify the materialistic characteristics of the lead glaze used for paving bricks during the late Unified Silla period in Korea. The samples were excavated from the Beopgwangsa Temple site, Pohang. As a result of observing the surface and cross-section of the glaze with a microscope, the study confirmed that the lead glaze demonstrates various traits of hydration, which were classified into four layers: Surface layer, hydration layer A, hydration layer B, and green layer. After measuring the composition of each layer with SEM-EDS analysis, the green layer was found to have been less affected by the external environment, which renders it highly reasonable to view the green layer as the original composition of the lead glaze. The green layer is a low-temperature glaze composed mainly of PbO and SiO₂ at a ratio of 8:2, with approximately 2% CuO acting as the main colorant. Comparing the green layer composition with those from Gyeongsang-do, it was confirmed that the mixture ratio of lead glaze materials was similar to other sites such as the Sacheonwangsa Temple site, the Cheonryongsa Temple site, and the Buseoksa Temple site.

• Journal of Conservation Science
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• 제27권1호
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• pp.75-90
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• 2011

At the beginning of the Chos$\breve{o}$n dynasty, punch'$\breve{o}$ng began as a simplified form of inlaid celadon, and in the two following centuries it developed into a popular folk craft in various styles and expressive decorations; overtime, it was increasingly made to resemble whiteware, and its production stopped after the Japanese invasion of Korea. In the present study, the body and glaze compositions of punch'$\breve{o}$ng were examined and compared with those of celadon and whiteware, whose compositions have previously been compared with those of Chinese ceramics. Here, the analyzed shards were organized into 28 groups based on their production sites and archaeological characteristics. For each group, the body and glaze compositions of several shards(usually three to five) were obtained, averaged, and compared with those of the other groups. These comparisons showed that the majority of the punch'$\breve{o}$ng bodies were formed, like those of celadon and whiteware, with mica-quartz porcelain stone, which was commonly used in Yuezhou, Jingdezhen, and other southern Chinese kilns. The glazes consisted of clay materials and flux components made from various proportions of wood ash, burnt limestone (glaze ash) and crushed limestone. Overall, the punch'$\breve{o}$ng glazes resembled the Kory$\breve{o}$ celadon and Kory$\breve{o}$ whiteware glazes more closely than the Chos$\breve{o}$n white wareglazes. However, the $TiO_2$ levels found in the tested punch'$\breve{o}$ng were low, similar to those of Chos$\breve{o}$n whiteware; this indicated that glaze stone was used as the clay component of the punch'$\breve{o}$ng glazes, as was the case for Chos$\breve{o}$n whiteware. This study of the material characteristics of punch'$\breve{o}$ng may be used as a comparative framework for analyzing ceramic shards discovered at current and future excavations within Korea.

• Journal of Conservation Science
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• 제27권1호
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• pp.61-74
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• 2011

The material characteristics of Chos$\breve{o}$n whiteware were investigated by analyzing and comparing the body and glaze compositions of whiteware shards excavated at the Kwangju royal kilns, Ch'unghyodong, and four other local-level kilns. In Korea, the rise of whiteware technology began in the early years of the Chos$\breve{o}$n dynasty, when the indigenous tradition of Kory$\breve{o}$ celadon was strongly influenced by the whiteware aesthetics of the Chinese Ming dynasty. The Kwangju royal kilns eventually made hard-textured whiteware of a quality equivalent to that of the Chinese by using type of porcelain stone that contained slightly less $Fe_2O_3$ and $TiO_2$ and slightly more $K_2O$ than that used for celadon. In contrast, the potters of Ch'unghyodong achieved the same level of quality by finding and using a totally different material: kaolinitic clay. The porcelain stone used at the Kwangju kiln was commonly found in Korea and south China, whereas kaolinitic clay (which has a high aluminum content) was typically found in north China, and was only rarely used in Korea. The flux component of the glaze compositions was mostly limestone, first in burnt form and later in crushed form, and the clay component was often glaze stone, which was a finer-grained porcelain stone with a higher proportion of feldspar. In the future, this comparative analytical study of Korean whiteware components should be extended to the $18^{th}$- and $19^{th}$-century kilns that are currently being excavated at a rapid pace.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제27권5호
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• pp.256-262
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• 2017

Digital ink-jet printing technology using ceramic ink, which is thermally stable at high temperature above $1000^{\circ}C$, has an advantage of eco-friendly process applicable to manufacturing products with an excellent durability and various designs. Recently, replacement from conventional manufacturing process to digital process using ink-jet printing technique has been significantly accelerated in ceramic tile industry. In this study, we investigated ink-jet printability of ceramic ink on ceramic tile. Cyan, magenta, yellow, black ceramic inks, which are digital primary color of ink-jet printing, were printed on glazed surface of ceramic tiles, and their printabilities were comparatively analyzed. High temperature sintering process is generally required for manufacturing ceramic products, thus effect of sintering process on printed pattern of ceramic ink was also investigated by analyzing ink penetration depth and ink dot area.