• The Research Journal of the Costume Culture
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• v.19 no.2
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• pp.309-315
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• 2011

Due to rapid growth of nail art industry, various materials and expression tools are have been developed. Increasing number of consumers favor diverse nail art techniques including painting and artificial tips in addition to basic care such as cuticle trimming or coloring. Accordingly, the diversity of polish colors has been settled as a concept of total fashion in addition to the clothes and accessories. As the result, nails may be damaged or discolored. A study the nail discoloration by using polish was purposed that contribute to the development of nail protective products. The tests were conducted with 20 college students for six months from March 3 to Aug. 28, 2009, using digital camera as the measurement apparatus. The students were classified into two groups which applied bright polish (white, beige, pink series) and dark polish (purple, blue, black series), and then divided into the groups applied and not applied the base coat which is known to be effective in preventing nail discoloration, and the groups applied and not applied tonic. The students applied polish for one week, and removed the polish with remover and photographed to examine the degree of nail discoloration. Dark colored polished resulted in earlier coloration and discoloration than the bright colored ones. Base coat could prevent coloration and the color changes of hyponychium and eponychium were lighter than the cases not applied with base coat. Tonic could delay coloration and reduced the color changes of hyponychium showing that tonic was effective for preventing coloration and discoloration of nail in addition to nutrition.

• Conservation Science in Museum
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• v.9
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• pp.51-58
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• 2008

Influence of lighting for exhibition normally used in museum on discoloration of relics and weakening of materials was reviewed, and influence of currently used lightings discoloration of dyed Korean paper similar to relic and change of material quality was directly tested. There were small differences in influence made on dyed Korean paper according to exhibition lighting, and based on these differences, method to select lighting safer for relics were explored. As a result of testing 4 types of fluorescent lamps, one lamp of them showed little influence on discoloration and change of material quality, which is judged to be proper for use in museum.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.73-81
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• 2010

The objective of this study was to evaluate the color stability of new silorane-based composite resin compared with methacrylate-based composite resins after immersion in 3 staining solutions. One silorane-based composite(Filtek P90) and 3 methacrylate -based composites(Filtek Z250, Filtek Z350, Tetric Ceram) were evaluated. Twenty disk-shaped specimens($10{\times}2mm$) of each of 4 composite resins were prepared. The specimens were then divided into 4 groups of 5 specimens each and immersed in 3 staining solutions( coffee, red wine, curry solution) or distilled water(control) for 28-day test period. Color of the specimens was measured with a spectrophotometer(Color Eye 7000A) using CIE $L^*a^*b^*$ color space relative to CIE standard illuminant D65 at baseline, 1day, 3days, 7days, 14days, 21days and 28days after staining. The color differences( ${\Delta}{E^*}_{ab}$) were calculated. The results were obtained as follows ; 1. The mean color changes(${\Delta}{E^*}_{ab}$) of the composites were greatest in curry solution, then red wine, coffee and distilled water, in decreasing order. 2. The mean color changes(${\Delta}{E^*}_{ab}$) of the composites were greatest in Z350, Z250, Tetric Ceram and P90, in decreasing order.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.161-166
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• 2000

Classified handmade Korean paper which has been commonly used as the material for the paper cultural assets divide into four classes. We irradiated xenon arc lamp, which has almost the same spectrum distribution as natural sunlight, to test photo-induced of discoloration according to PEG molecular weight and concentration. So, we reach the followings. 1) Unbleached handmade Korean paper with PEG showed rapid decrease of brightness for 10 hours after photo-irradiation, regardless of molecular weight of PEG, but, after 10 hours, it showed gradual increase of brightness. From this, it proved that there was an effect of preventing discoloration of photo-irradiation. 2) Chemical bleached handmade Korean paper showed increase of brightness after 20 hours. Though time was delayed in increase of brightness, there was also an effect of preventing discoloration of photo-irradiation in chemical bleached paper. 3) Handmade Korean paper made with abet-mosk showed the lowest of brightness when it was tested on 400-20% PEG. Before photo-irradiation, the brightness of paper, applied it, was the lowest, but it showed the least difference of brightness after photo-irradiation. From this, it proved that there was the greatest effect of preventing discoloration in this paper. 4) Preventing yellowish, the first phenomena by photo-irradiation ageing with applying PEG was proved that there was the decrease of value of $b^*$ +, and increase value of $L^*$, which could fairly prevent decrease of brightness.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.197-202
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• 2005

Generally, a semiconductor chip measured with a few micro units is captured by line scan camera for higher inspection accuracy. However, the faulty inspection requires an exact boundary detection algorithm because it is very sensitive to scan speed and lighting conditions. In this paper we propose boundary detection using subpixel edge detection method in order to increase the accuracy of bump faulty detection on chips. The bump edge is detected by first derivative to four directions from bump center point and the exact edge positions are searched by the subpixel method. Also, the exact bump boundary to calculate the actual bump size is computed by LSM(Least Squares Method) to minimize errors since the bump size is varied such as bump protrusion, bump bridge, and bump discoloration. Experimental results exhibit that the proposed algorithm shows large improvement comparable to the other conventional boundary detection algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.793-799
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• 2007

Generally, a semiconductor chip measured with a few micro units is captured by line scan camera for higher inspection accuracy. However, the faulty inspection requires an exact boundary detection algorithm, because it is very sensitive to scan speed and lighting conditions. In this paper we propose boundary detection with subpixel edge detection in order to increase the accuracy of bump faulty detection on chips. The bump edge is detected by first derivative to four directions from bump center point and the exact edge positions are searched by the subpixel method. Also, the exact bump boundary to calculate the actual bump size is computed by LSM(Least Squares Method) to minimize errors since the bump size is varied such as bump protrusion, bump bridge, and bump discoloration. Experimental results exhibit that the proposed algorithm shows large improvement comparable to the other conventional boundary detection algorithms.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.306-316
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• 2017

The purpose of this study was to evaluate the effects of exposure to various children's drinks on the color stability of anterior primary teeth and different esthetic restorative materials clinically used in pediatric dentistry. Exfoliated maxillary primary central incisors that had been unaffected by caries were chosen as control group. Maxillary primary central incisor-shaped specimens made of strip crown and Nu-smile zirconia crowns were chosen as test groups. Polished strip resin crowns were additionally prepared to compare with unpolished strip resin crown. Each specimen and teeth were divided into 4 groups in which the test samples (n=5 each) were immersed in 4 different drinks (distilled water, cola, grape juice, jelly juice) for 6 days. In all 4 drink groups, all specimens generally showed increasing ${\Delta}E^*$ value (color difference) with time. Polished resin strip crown had higher ${\Delta}E^*$ value than the unpolished in cola, grape juice and jelly juice groups. ${\Delta}E^*$ value of zirconia crown in cola, grape juice and jelly juice groups were significantly different (p < 0.05). In conclusion, dietary control of children's drinks is required for preventing discoloration of restorative materials.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.112-118
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• 1978

Four domestic frying oils (soybean, corn, rapeseed and rice bran oil) were studied on their changing properties according to thermal oxidation by means of chemical analysis of their compositions and measurements of various physical and chemical properties. The content of linoleic acid which is an essential unsaturated fatty acid and the total amount of unsaturated fatty acids were highest in soybean oil (53.2% and 80.3% respectively) among the unheated frying oils and the degree of its thermal degradation was lowest during the continuous heating period for 48 hours at $180^{\circ}C$. However in general, the contents of unsaturated fatty acids were sharply decreased by thermal oxidation whereas the saturated fatty acid contents ranging 10-17% were not changed considerably, which largely agreed with the results of iodine value measurements. The free acid and peroxide values were also lowest in soybean oil (0.09 and 5.6 respectively) among the unheated oils whereas an anomalously high free acid value was observed in rapeseed oil (54.8) which was packed in unleveled glass bottles. Such a high value is probably ascribed to the photo-catalyzed oxidation during storage. The viscosity measurements have shown similar values before heating, but after thermal oxidation for 32 hours the rapeseed and rice bran oils became too thick to measure viscosity by capillary flow method with heavy darkening in color.