• Journal of Life Science
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• v.21 no.4
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• pp.610-612
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• 2011

We developed a spectrophotometric assay for the quantitative determination of chlorogenic acid based on the formation of green pigment at $50^{\circ}C$ under glycine and alkaline conditions in 96-well plates. The formation of green pigment was linear with a series of chlorogenic acid concentration (0-$300\;{\mu}M$). Using this method, the content of chlorogenic acid (12.42 mg/g dry weight) in the leaves of blueberry was quantified. This method is high-throughput, cost-effective, rapid, and easy to perform.

• Journal of the Korean Ceramic Society
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• v.36 no.4
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• pp.333-342
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• 1999

This research was performed to investigate how the basic glaze change affected colour development at high temperature with a stable colorant (spinel structure CoAl2O4 pigment) The compounded pigment which is widely used for porcelain was also tested for the basic glazes adaptability. The data from the test were recorded in a computer data-base program. Therefore could be easily used in the study related with a pottery field. CoO : Al2O3 system spinel pigment of barium glaze lime glaze zinc glaze lead glaze and talc glaze were chosen for this study. The colors of Cobalt blue bright blue, blue purple were seen at the wave lengths of 455-480nm at the firing temperature of 1250$^{\circ}C$. Stable color were obtained from lime glaze bar-ium glaze zinc glaze. All the information in the database were used to examine all the possible result of the test in the study of porcelain. When the test results database were examined in all temperature ranges the lack of adhesion with the pigment occurred at the temperature of 1150$^{\circ}C$. The lack of adhesion is seen due to vaporization of the lead glaze.

• Journal of the Korean Ceramic Society
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• v.47 no.3
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• pp.237-243
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• 2010

This research examines using Rice Husk Ash, $Cr_2O_3$ in producing the pink-red color. It studies the formation of cassiterite and malayaite crystallites, the primary factors in producing the pink-red color, in relation to the application of $Cr_2O_3$ to examine its coloring mechanism. In addition, the research intends to identify the optimum synthesizing temperature and maintaining time for crystallization of malayaite, a stable pink-red colorization factor in high temperature glaze during $Cr_2O_3$-$SnO_2$-CaO-$SiO_2$ family pigment synthesis. The optimum substituting contents is Rice Husk Ash : Quartz = 1 : 2, and the optimum temperature is suggested at $1300^{\circ}C$ for 2 h based on analysis results by XRD, FT-IR, Raman microscope, SEM and UV-vis.

• Journal of the Korean Ceramic Society
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• v.45 no.3
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• pp.172-178
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• 2008

This paper described the study of a sphene-pink pigment based on $Cr_2O_3-SnO_2-CaO-SiO_2$ system exhibits stable pink-red color at high temperature. This study is focused on the optimization of the synthesis parameter such as temperature and holding time for the formation the Malayaite crystal. Malayaite crystal is sensitively influenced by the synthesizing temperature, maintaining time and contents of substituting chromium. The crystal phases formed at different temperatures exhibits various color. The optimum temperature is suggested at $1300^{\circ}C$ for 2 h and substituting contents of Cr for Sn is 0.01 mole. The maximum substituting contents is 0.02 mole based on analysis results by XRD, FT-IR, SEM and UV-vis.

• Journal of Photoscience
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• v.9 no.2
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• pp.74-77
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• 2002

Chlorophyll (Chi) d was assigned to an antenna pigment of red algae in 1943, but its presence and function in red algae have not been necessarily clear for a long time. In 1996, it was shown that Chi d functioned as a major antenna pigment in a peculiar oxygenic photosynthetic prokaryote, Acaryochloris marina, isolated as a symbiont of a colonial ascidian from coral reefs. This finding evoked the necessity for reexamination of the presence and function of Chi d in red algae. We found Chi d in methanol-extract from several marine red algae, and the relative content was high in one species, Ahnfeltiopsis flabelliformis. Absorption and fluorescence spectra, HPLC analysis, and NMR and mass spectroscopy characterized Chi d extracted from the red algal thalli, and those were essentially identical to those of Chi d isolated from A. marina. However, micro-spectrophotometric analysis suggested that Chi d was not an actual constituent of the red algae but came from epiphyte(s) attached to surface of red algal thalli.

• 한국문화재보존과학회:학술대회논문집
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• 2002.02a
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• pp.12-20
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• 2002

The analysis of danchung pigments at the Geunjeongjeon Hall in the Gyeongbokgung Palace were carried out by EXRF and MXRD. The analytical results showed that mineral pigments were employed for the inside of the Geunjeongjeon Hall. The main ingredients of green pigments were chalcanthite and celadonite. Red pigment was cinnnabar. It was also revealed that synthetic pigments were applied for the outside of the Hall. Yellow pigment was chrome yellow. The main ingredients of red pigments were red lead and hematite. Green pigments were emeral green and chrome green. Lazurite was employed for blue pigment and titanium dioxide for white one.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.3
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• pp.399-407
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• 1998

The infrared reflection coatings with pigment can be used to protect the surfaces of combustible materials exposed to fire. To obtain high reflectivities in the infrared range (0.5-10.mu.m) important to fire, several dielectric pigments, such as titanium dioxide, iron oxide, and silicon, can be synthesized to polymer coatings. The theoretical analysis shows that the coating design with particles diameter in the 1.5 to 2.5.mu.m range and volume fraction in the 0.1 to 0.2 range is estimated to be optimal. In the analysis of the radiation, the dependent scattering, absorption by polymeric binder, and the internal interface reflection are considered. In addition, the temperature distribution in the semi-transparent coating layer and an opaque substrate (PMMA) is also presented.

• Journal of Conservation Science
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• v.35 no.4
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• pp.345-361
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• 2019

This study demonstrates the application of hyperspectral analysis as a pigment identification method for modern and contemporary Dancheong, the polychrome surface on traditional Korean wooden buildings. In particular, green pigments are the focus of this study. Green pigments in modern and contemporary Dancheong have the largest variation of materials and show a noticeable timeline. Thus, they are most suitable for estimating the manufacture or restoration period of Dancheong. Hyperspectral analysis is a noncontact, long-distance measurement technique that has advantages in the field of Dancheong analysis. It is capable of identifying both organic and inorganic pigments, unlike existing analysis methods. For this experiment, green and other pigments used during the modern and contemporary era were selected and made into painted samples under various mixing conditions that reflect their actual uses. Through hyperspectral analysis, their reflectance characteristics were observed, which enables the derivation of four main features that can distinguish the type of pigments used for color mixture. Based on these, a pigment identification system was designed in the form of a flowchart, and its utility was confirmed through site application. Despite some limitations at this stage, the technique can be complemented by considering proper measurement methods or the continuous accumulation of samples and data. If a database on various materials, mixing ratios, painting techniques, and other external interference factors is developed in future research, it would provide the foundation for a faster and safer analysis environment of Dancheong sites.

• Journal of the Korean Ceramic Society
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• v.51 no.3
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• pp.184-189
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• 2014

Electric arc furnace dust (EAFD) is a solid waste generated by the steel-scrap recycling process. It mainly consists of zinc oxides (ZnO), alumina ($Al_2O_3$), iron oxides ($Fe_2O_3$), and silica ($SiO_2$). Here we report the preparation and characterization of blue ceramic pigments using EAFD powder as a starting material. $(Zn(EAFD),Co)Al_2O_4$ blue ceramic pigment was prepared by the solid-state reaction method. The color characteristics of the pigment obtained were compared with those of pure $CoAl_2O_4$. The new pigment was characterized using XRD, CIE-$L^*a^*b^*$ color-measurements, SEM, and EDX. The XRD analysis revealed that the $(Zn(EAFD),Co)Al_2O_4$ pigment was composed of mainly the spinel phase of $(Zn,Co)Al_2O_4$. The $Zn(EAFD)_{0.25}Co_{0.75}Al_2O_4$ pigments showed a vivid blue color with a $b^*$ value of -28.64 and a good glaze stability with a transparent glaze.

• KIEAE Journal
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• v.9 no.1
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• pp.77-83
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• 2009

In this experiment, we used different addition ratio of the pigment and straw, to improve the decorative effect of the finishing touch while finding the kinds of clay colors taking on many sophisticated images, through the comparison between the various colors and textures of the surface. (1) To test the plaster material, added were the pigment of Red, Yellow, Black, and Green by the percentages of 0.5, 1, 1.5, 2, and 2.5, respectively, followed by the analysis of the color changes of the plaster material using the Photoshop (RGB). The results showed the bigger the addition ratio of the red color is, the higher the numeral values of RGB after it dried. However the brightness after drying didn't showed a big difference depending on the addition ratio. With the addition of the yellow pigment, the color difference between after and before drying was bigger in the order of Blue, Green and Red; the brightness increasingly rose while the saturation changed little. (2) When we scratched the plaster surface with U and V shape carving knives, the U knife didn't make a clean shape digging around the clay plaster material but with smooth textures, while the V knife made a clean cut, which represents its readily use in terms of the decorative function of the clay plaster. (3) In an experiment the surface texture was tested with different lengths and additions ratio of the straw, addition of 2cm straw by 1, 2, and 3% presented the most appropriate surface of the plaster.