• Journal of Powder Materials
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• v.10 no.6
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• pp.415-421
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• 2003

The study for producing the flake powders by milling of aluminum foil and gas atomized powders was carried out. The effects of lifter bars on the ball motions and milling of aluminum foils were also investigated. The aluminum foils were laminated each other, elongated, fragmented into small foils and finally formed into the flake powders during the dry ball-milling. The spherical atomized-powders were milled to coarse flake powders with high aspect ratio and then changed to fine flake powders with lower aspect ratio. Even though long times were required for making flake powders by milling of foils, the water covering areas of them were higher than those of powders milled using gas-atomized powders, suggesting aluminum foils were more plastically deformed by micro-forging. On the other hand, as the number of lifter bars increased, the necessary rotation speeds of milling jar for cascading mode and cataracting mode decreased drastically. It was possible to achieve same quality of milled flake powder by using the lifter bars under the lower milling speeds. The painting test showed that the appearance of painted surface was good and optimum content range of aluminum paste in car paint to maximize the degree of gloss was 3-5%.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.23-29
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• 2010

Pigment concentrates with violet-red color and sweet taste were obtained from purple-fleshed sweet potato(PFSP) using ethyl alcohol and water. Extract from general potato(GP) were used as a control. The relative stability of PFSP pigment concentrate(PFSPPC) in a storage test over 15 days was confirmed in the order of dark > fluorescence > sun-light irradiation. The relative stability of GP pigment concentrate(GPPC) in a storage test over 15 days was confirmed in the order of sun-light > fluorescence > dark storage. The RRP of PFSPPC was higher than that of GPPC, but the color strength of GPPC was 1/2 that of PFSPPC. Treatment of PFSPPC with aluminum potassium sulfate(0.2~0.3%, w/w) best improved its stability. The improved RRPs of PFSPPC were 45.16~47.31% in sun light irradiation, 55.91~60.22% in fluorescence irradiation, and 76.34~75.97% in dark storage conditions. In substituting aluminum potassium sulfate for chitosan, an amount of 0.2~0.3%(w/w) was suitable, giving similar results in improving pigment stability for all concentrates tested. Also, freeze-dried PFSPPC powder was manufactured as a substitute for dextrin, and also as a substitute for chitosan to the extent of 0.25%(w/w). The results of storage stabilite for freeze-dried PFSPPC and GPPC powder over 15 days, irradiation were, PRRs of 74.47~89.36% and 61.54~76.92%, respectively. The stability improving effect of freeze dried PFSPPC powder was confirmed by the results of storage experiments at various conditions. The use of freeze-dried PFSPPC powder was therefore confirmed to be an effective treatment for general foods.

• Journal of Conservation Science
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• v.38 no.4
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• pp.327-333
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• 2022

Sri Lanka has four types of mural painting styles; Classic, Late Classic, Kandyan, and Southern styles, but there is little research on scientific analysis for mural paintings. In this study, we analyze white, yellow, and red clay pigments which were collected from ancient producing sites. Analyzing pigment samples shows that samples are containing aluminum oxide(Al₂O₃) and silicon dioxide(SiO₂) which are connected to the soil. And a degree of iron oxidation determines yellow or red colors. To understand the characteristics of clay pigment samples, we go over previous pigment analyses of mural paintings in Sri Lanka. Kaolin is identified after the 17^th century, yellow and red ochre are applied in early periods, Classic and Late Classic styles. The change in raw materials of pigments occurred in the 17^th century.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.13 no.1
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• pp.7-14
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• 1987

Production of shikonin derivatives through cell suspension culture of Lithospermum erythrorhizon was investigated. Optimal concentrations of IAA and kinetin on the growth of cell suspension were 0.2 and 0.1 ppm respectively. Pigment content was markedly increased when aluminum oxide was added to the production medium and its optimal concentration was 1.5g/70ml medium. The most effective concentration of IAA was 0.5 ppm and the production of pigment did not depend on the kinetin concentration.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.3 s.116
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• pp.66-71
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• 2006

The objective of this study was to find in what color Hanji(Korean hand-made paper) is dyed when it is dyed with a pigment extracted from clove tree using different kinds of mordant, and how the paper is discolored and variety of strength under the condition of accelerated aging test. The results of this experiment are as follows. The Hanji dyed with aluminum acetate mordant was colored yellowish brown at pH 4.82, discoloration after aging was as much as a slight difference of color was recognized, and the decrease of strength after aging test was small. Thus, the method using aluminum acetate mordant was usable in coloring Hanji. The second most useful Hanji dyeing moth of was using distilled water and ferrous sulfate mordant, which dyed Hanji light brown at pH 6.03. However, when pigment was extracted using distilled water and copper sulfate mordant was used, discoloration was satisfactory but strength decreased too much and pale brown was obtained. Thus, this method was not usable.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.264-269
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• 2008

For the synthesis of lead chromate pigments, we investigated the characteristics of particle growth with reacting conditions in the synthetic process, the effect of additives, and its micro-capsulation. The more tiny and uniform dispersion particles could be obtained at a lower pH and diluter intial concentration. The variation range of average pigment size was increased with the agitating speed. The pigment size could be controlled by adding aluminum sulfate as an additive, which maintained the optimum particle dispersion. It was found that the optimum micro-capsulation conditions were pH 9~10 and above $90^{\circ}C$ during the micro-capsulation of lead chromate pigment, and below 0.5% humidity after micro-capsulation.

• Corrosion Science and Technology
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• v.6 no.4
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• pp.206-210
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• 2007

Aerospace aluminum alloys such as Al alloy 2024-T3 and 7075-T6 are subject to localized corrosion due the existence of intermetallics containing Cu, Mg or Zn. Chromate is currently widely used in the aerospace industry as the corrosion inhibitor for these alloys. However, chromate needs to be replaced due to its strong carcinogenicity. In this study, an extensive pigment screening has been performed to find replacements for chromates. Different categories of inhibitors were evaluated by immersion tests, DC polarization tests and other methods. Phosphates, zinc salts, cerium salts, vanadates and benzotriazole were found to be effective inhibitors for AA7075. Among those inhibitors, zinc phosphate was found to be the most effective in our novel, silane-based, one-step aqueous primer system. The performance of this primer is comparable to that of currently used chromate primers in accelerated corrosion tests, while it is completely chromate-free and its VOC is about 80% less than that of current primers. Studies by SEM/EDS showed that the unique structure of the superprimer accounts for the strong anti-corrosion performance of the zinc phosphate pigment. The self-assembled stratified double-layer structure of the superprimer is characterized by a less-penetrable hydrophobic layer at the top and a hydrophilic layer accommodating the inhibitors underneath. The top layer functions as the physical barrier against water ingress, while the lower layer functions as a reservoirfor the inhibitor, which is leached out only if the coating is damaged by a scratch or scribe. The presence of a silane in the primer further improves the adhesion and anti-corrosion performance of the primer.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.295-299
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• 2022

In this paper, paint-free metallic plastic material, polypropylene (PP) and acrylonitrile styrene acrylate (ASA) materials were investigated on the applications for bumper skid plate and outside mirror housing parts. In order to maximize metallic effect, type, size and content of aluminum pigment were optimized based on flop index. Hybrid aluminum pigments with different aspect ratios were used to conceal weld lines. By controlling the fluidity of the material, the flow mark problem, generated on the surface of the part, was resolved. We also investigated the surface defects of flow and weld lines by using the developed modeling and simulation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.1
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• pp.48-53
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• 2003

The objective of this study was to find in what color Korean handmade paper(Hanji) is dyed when it is dyed with a pigment extracted from waste onion peelings using different kinds of mordant, and how the paper is discolored and variety of strength under the condition of accelerated aging test. The results of this experiment are as follows. 1. Korean handmade paper was dyed in different colors according to the kinds of mordant. Mainly it was dyed in orange-brown, and sometimes in gold or khaki. 2. Korean handmade paper dyed was not discolored much, which suggests that the pigment is strong under the condition of aging. 3. As for durability, Korean handmade paper dyed in gold was strongest. Korean handmade paper, to which aluminum sulfate, iron sulfate or sodium dichromate was applied as mordant, had poor durability. Thus, these were not suitable as mordant.

• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.610-617
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• 2004

For preparation $\alpha$-Al$_2$O$_3$ platelets having 20 $\mu$m in average diameter and 0.2∼0.3 $\mu$m in thickness, we have prepared aluminum hydroxides gel by using aluminum sulfate and sodium sulfate as starting materials. In this study, we investigated the effect of the amount of sodium phosphate on particle size, morphology and thickness of $\alpha$-Al$_2$O$_3$ platelets. When sodium phosphate was not added to aluminum hydroxides gel, most of $\alpha$-Al$_2$O$_3$ platelets had hexagonal shape but the thickness was over 1.0 $\mu$m, and this sample was not adequate for pearlescent pigment. On the other hand, introduction of sodium phosphate caused an increase of aspect ratio (particle diameter/thickness) with a decrease in $\alpha$-Al$_2$O$_3$ platelet thickness.