• Journal of Technologic Dentistry
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• v.4 no.1
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• pp.5-7
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• 1982

This study was performed to examine the effect of repeated firing on porcelain color stability. Sixty sepcimens of generally uniform size and shape(9.7 12mm)were prepared using the manufactorer's specifications and among them 50 specimens that showed no defect after firing procedure were selected. All samples, abraded with sandpaper disc, ultrasonically cleaned, and air fired to amedium glaze were devided into 10 groups according to the number of repeated firing and, upon completion, mounted on a 13 by 16cm board. 30 persons(five dentists, ten dental techanicians, and fiftheen students) were asked to compare the samples for variations, in hue, chroma and value under natural and artificial light. The results were as follows:(1) There were no color change detected in the first four firings.(2) Slight color change were noticed in subsequent firings(ie: greater decreases in value with slight increases In chroam)(3) However, the hue remained constant in all 10 groups after repeated firings.

• The Journal of Advanced Prosthodontics
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• v.6 no.6
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• pp.427-433
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• 2014

PURPOSE. Surface color is one of the main criteria to obtain an ideal esthetic. Many factors such as the type of the material, surface specifications, number of firings, firing temperature and thickness of the porcelain are all important to provide an unchanged surface color in dental ceramics. The aim of this study was to evaluate the color changes in dental ceramics according to the material type and glazing methods, during the multiple firings. MATERIALS AND METHODS. Three different types of dental ceramics (IPS Classical metal ceramic, Empress Esthetic and Empress 2 ceramics) were used in the study. Porcelains were evaluated under five main groups according to glaze and natural glaze methods. Color changes (${\Delta}E$) and changes in color parameters (${\Delta}L$, ${\Delta}a$, ${\Delta}b$) were determined using colorimeter during the control, the first, third, fifth, and seventh firings. The statistical analysis of the results was performed using ANOVA and Tukey test. RESULTS. The color changes which occurred upon material-method-firing interaction were statistically significant (P<.05). ${\Delta}E$, ${\Delta}L$, ${\Delta}a$ and ${\Delta}b$ values also demonstrated a negative trend. The MC-G group was less affected in terms of color changes compared to other groups. In all-ceramic specimens, the surface color was significantly affected by multiple firings. CONCLUSION. Firing detrimentally affected the structure of the porcelain surface and hence caused fading of the color and prominence of yellow and red characters. Compressible all-ceramics were remarkably affected by repeated firings due to their crystalline structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2150-2156
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• 2009

The effects of MgO and coloring agents on the physical properties and color of zirconia based ceramics with glass frit were studied. The addition of MgO was effective on the coloring of zirconia-20wt% glass frit system. Major factor on the coloring was turned out to be sintering temperature. Coloring agents was turned out to be more effective than the addition of MgO on the coloring of zirconia base ceramics. Specimen without glass frit showed drastic change in color, while specimen with 20wt% glass frit revealed a limited change in color. This means that the addition of glass frit suppresses the coloring of zirconia based ceramics. The effect of sintering temperature on coloring revealed little change in color.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.212-219
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• 2005

As the development of digital and technological sophistication, architectural speculation hierarchy had been more and further diversified and brought on the changes with system of architectural color meaning. Architectural color had been influences on evocation of effect and meaning by association, had the attributes of communication with human being, in common with precision, non-verbal and non-quantitative creative field. Color could not been defined as one conclusively standard symbol and figured out in inter-relationship with correlation, mental status and interaction. Color in architecture could been promptly defined as the tool of visualization in building or structure through the essential criterion to be measured with shape, space and author's thought. In consequence, color in architecture could been re-defined as the speculation concept for real characteristics creation(color as design factors on architect and color to be expressed by program) in itself, and color supporting system as for transposition of light and space enlargement scheme. Consequently, color in architecture could been turnover from perceived color to anthropological color through the real value creation scheme in itself.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.71-71
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• 2003

This study was conducted to investigate effects of dietary pigment sources on shell color of juvenile abalone, Haliotis discus hannai. Three replicate groups of the abalone, average weight 173 mg, were fed the diets containing various pigment sources such as Porphyra powder, Spirulina, yeast astaxanthin and paprika extract for 16 weeks. Survival and weight gain were not affected by dietary pigment sources (P>0.05). Shell color of abalone fed diets containing Porphyra powder and Spirulina was approached to yellow-red and orange which are similar to shell color of wild abalone. However, shell color of abalone fed the diets containing yeast astaxanthin and paprika extract were similar to that of control diet showing bright green. Porphyra powder and Spirulina contain not only fat-soluble pigment such as chlorophyll and carotenoids but also water-soluble pigment such as phycoerythrin and phycocyanin. These results would be useful information to change shell color of abalone in aquaculture.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.3
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• pp.617-628
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• 2001

Cotton and silk fabrics dyed with brazilein(Caesalpinia Sappan), berberine (Phellodendron Amurense), and shikonin(Lithospermum Erythrorhizon) were stored in the air, in the water, and under the ground for about one year. The change of the color, the flexibility, and the breaking strength were measured at the intervals of few weeks. The results are as follows; 1. The color of the fabrics changed most extensively in the fabrics that were under the ground, then in the order of the ones that were in the water, and in the air. The color of the fabrics changed to the achromatic color over the time. 2. The flexibility change among the dyes was similar. All the fabrics became stiff under the ground and in the water over the storage time. 3. In general, cotton and silk fabrics dyed with berberine showed better strength retention than the fabrics dyed with other substances. 4. The strength retention of cotton fabrics was high in the order of the fabrics which were in the air, in the water, and under the ground. Only minuscule change occurred in the strength of the cotton fabrics. The strength of the fabrics that were in the water and under the ground decreased remarkably after 30 weeks and 20 weeks respectively. 5. The strength retention of silk fabrics was high in the order of the fabrics which were in the air, under the ground, and in the water. In the air, the strength on silk fabrics decreased rapidly after 30 weeks. In the water, the strength of silk fabrics decreased more rapidly than that of the cotton fabrics. Under the ground, the strength retention of silk was higher than that of cotton.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.242-250
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• 1996

Glasses of Na2O-Al2O3-SiO2 system were prepared and ion-exchange characteristics change of properties and bactericidal effects by Na+↔Ag+ ion exchange were studied. Parent glasses with three compositions of varying Na2O in the 20~30 wt% were ion-exchanged in the molten salt of 2 mol% AgNO3+98 mol% NaNO3 at 320~36$0^{\circ}C$ for 15~16min. Amount of ion exchange and penetration depth of Ag+ ion increased with Na2O content in the parent glass ion exchange temperature and time. After ion exchange densities and Vickers hardness of the glasses increased and the glasses showed yellow-brown color and as amount of ion exchange increased the color turned deep because partial reduction and agglomeration of Ag+ into Ag0 results in absorption of visible light. After ion exchange chemical durability of the glass to wter was enhanced compara-bly that weight loss and change of surface of the glass were not found for the leaching test in 5$0^{\circ}C$ K.I water for 240hrs. Bactericidal effect of ion exchanged glass on Staphylococcus aureus and E. coli was determined by microorganism test and bactericidal effect increased with amount of ion exchange and incubation time.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.113-123
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• 2016

The purpose of this study is to look into the effect of wearing color lenses on one's image and was based on 221 college students in Gyeonggi-do and Gangwon-do. I examined how it appears as the evaluation factor visually. After by looking in the different image effect and relevance as to the classified evaluating factors, I tried to look into what effect the color lenses has on woman eye and image. The result is as follows. It appears that wearing color lenses makes one look fancier, more attractive, sophisticated, and favorable, whereas not wearing color lenses makes one look softer, weaker, more innocent, and comfortable. Analyzing these evaluations showed that wearing color lenses has most to do with attractiveness followed by pureness, familiarity, and decorativeness in order, whereas not wearing color lenses has most to do with familiarity followed by attractiveness, pureness, and decorativeness. It is considered that eyes with color lenses on them make the person seem decorative, attractive, and pure, which brings effect of improving one's eye and face image. Analyzing the correlation between each color lenses-wearing factor and one's image showed that when a person is wearing color lenses, the more the person is considered decorative, pure, and attractive, the more it has to do with improving the person's eye and face image. The result, therefore, shows that wearing color lenses makes one's eye and face image attractive, pure, and decorative, and wearing them is an important means to improve one's eye and face image.

• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.283-291
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• 2003

The purpose of this research was to analyze and improve the experiment, observing the color change under compression on the equilibrium of $2NO_2\;{\rightleftarrow}\;N_2O_4$ system, described in high school and general chemistry textbooks. Chemistry textbooks described that the reddish brown color got lighter on the compression of $2NO_2\;{\rightleftarrow}\;N_2O_4$ system. This misinterpretation was due to no consideration of $NO_2$ concentration increase by the volume decrease. In order to propose a correct interpretation, the changes of color and temperature on compression were quantitatively measured and compared with theoretical studies. In addition, an improved experiment, excluding the effect of $NO_2$ concentration increase, was proposed to observe only the color change of the net equilibrium shift.

• Journal of Korean Dental Science
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• v.8 no.2
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• pp.49-56
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• 2015

Purpose: The effect of accelerated aging on color stability of various dual-cured self-adhesive resin cements were evaluated in this study. Materials and Methods: Color stability was examined using three different brands of dual-cured self-adhesive resin cements: G-CEM LinkAce (GC America), MaxCem Elite (Kerr), and PermaCem 2.0 (DMG) with the equivalent color shade. Each resin cement was filled with Teflon mold which has 6 mm diameter and 2 mm thickness. Each specimen was light cured for 20 seconds using light emitting diode (LED) light curing unit. In order to evaluate the effect of accelerated aging on color stability, color parameters (Commission Internationale de l'Eclairage, CIE $L^*$, $a^*$, $b^*$) and color differences (${\Delta}E^*$) were measured at three times: immediately, after 24 hours, and after thermocycling. The $L^*$, $a^*$, $b^*$ values were analyzed using Friedman test and ${\Delta}E^*$ values on the effect of 24 hours and accelerated aging were analyzed using t-test. These values were compared with the limit value of color difference (${\Delta}E^*=3.7$) for dental restoration. One-way ANOVA and Scheff's test (P<0.05) were performed to analyze each ${\Delta}E^*$ values between cements at each test period. Result: There was statistically significant difference in comparison of color specification ($L^*$, $a^*$, $b^*$) values after accelerated aging except $L^*$ value of G-CEM LinkAce (P<0.05). After 24 hours, color difference (${\Delta}E^*$) values were ranged from 2.47 to 3.48 and $L^*$ values decreased and $b^*$ values increased in all types of cement and MaxCem Elite had high color stability (P<0.05). After thermocycling, color change's tendency of cement was varied and color difference (${\Delta}E^*$) values were ranged from 0.82 to 2.87 and G-CEM LinkAce had high color stability (P<0.05). Conclusion: Color stability of dual-cured self-adhesive resin cements after accelerated aging was evaluated and statistically significant color changes occurred within clinically acceptable range.