• 한국세라믹학회지
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• 제53권4호
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• pp.450-455
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• 2016

Color change in single-crystal, yellow, red, purple, and colorless cubic zirconias (CZs) was investigated as a function of annealing in vacuum and air atmosphere at $800-1400^{\circ}C$ for 30 min, for development of a damascene process of plugging a precious metal paste at the elevated temperature. Coloring-element contents of the CZs were evaluated using WD-XRF, and the color change determined visually by naked eye, and using a digital camera and UV-Vis-NIR color analyzer. WD-XRF showed that all of the CZs had cubic-phase stabilizer elements and coloring elements. All CZs that underwent vacuum annealing exhibited a slight color change at $<900^{\circ}C$, while their colors began to change to black at $1100^{\circ}C$, and became opaque black at $1400^{\circ}C$. After air annealing, there was almost no color change up to $1400^{\circ}C$. Since red and purple CZs showed greater color difference (CD) values than the others, the degree of CD is likely to depend on the original color of the CZ due to the different stabilities of their coloring elements during annealing. Based on our results, it is suggested that annealing in air at $<900^{\circ}C$ is advantageous, and assorted colored CZs can be used for precious metal damascene.

• 조명전기설비학회논문지
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• 제30권2호
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• pp.1-10
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• 2016

A system which provides multispectral near-IR and visible gray images of objects is constructed and an algorithm is derived to acquire a natural color image of objects from the gray images. A color image of 24 color patches is obtained by recovering their CIE (International Commission on Illumination) LAB color coordinates $L^*$, $a^*$, $b^*$ from their gray images using the algorithm based on polynomial regression. The system is composed of a custom-designed LED illuminator emitting multispectral near-IR illuminations, fluorescent lamps and a monochrome digital camera. Color reproducibility of the algorithm is estimated in CIELAB color difference ${\Delta}E^*_{ab}$. And as a result, if yellow and magenta color patches with around 10 ${\Delta}E^*_{ab}$ are disregarded, the average ${\Delta}E^*_{ab}$ is 2.9, and this value is within the acceptability tolerance for quality evaluation for digital color complex image.

• 한국수산과학회지
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• 제57권1호
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• pp.88-97
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• 2024

The underwater color environment was assessed by conducting color calculations based on underwater spectral irradiance measurements at various depths. Changes in the distribution of underwater spectral irradiance values between 1 and 3 m, exhibited similar trends in areas Stn. 1, 5, and 6. Likewise, changes between 5 and 20 m displayed comparable patterns in areas Stn. 1, 2, 4, and 6. Color values for each observed area fell between 0.14 and 0.26 (x-values) and 0.2 and 0.36 (y-values), with the y-values exhibiting a variation 1-3 times greater than the x-values. Color a_* and b_* values ranged from a maximum of -17 and -6 to a minimum of -63 and -30, respectively. By classifying fishing grounds based on observed variations, Stn. 1, 9, Stn. 2, 3, Stn. 7, 8 and Stn. 4, 5, 6 were grouped independently. Particularly, Stn. 5, 6, 7, and 8 were categorized into distinct groups that could be visually differentiated, especially when considering the significant changes in color a_* as the water depth increased from 10 to 20 m. Tokyo Bay were classified into different color groups, and Wakayama Prefecture offshore was classified into the same color group as the surveyed fishing grounds.

• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.213-222
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• 2017

Heat treatment of wood is an attractive alternative environmentally-friendly treatment to add value of less valuable woods by improving color, dimensional stability, and natural durability. To improve the color properties of Korean white pine (Pinus koraiensis) and royal paulownia (Pauwlonia tomentosa), we treated the woods at $160^{\circ}C$, $180^{\circ}C$, $200^{\circ}C$, and $220^{\circ}C$ for 2 hours. Color change after heat treatment was evaluated using the CIE-Lab color system and survey was conducted to determine the consumer preferences towards color of heat-treated wood. Lightness ($L^*$) decreased with increasing temperature and the higher degree of change was obtained in royal paulownia. The red/green chromaticity ($a^*$) in both wood decreased after heat treatment at $160^{\circ}C$, and constantly increased after heat treatment at $180^{\circ}C$ to $220^{\circ}C$. Yellow/blue chromaticity ($b^*$) in Korean white pine tended to increase after heat treatment at $160^{\circ}C$, then decreased gradually afterwards. In royal paulownia, $b^*$ values linearly increased with increasing temperature. Overall color change (${\Delta}E^*$) increased with increasing temperature with higher degree obtained in royal paulownia. Samples with the clamps in both wood species showed lower degree of the change in $L^*$, $a^*$, b and ${\Delta}E^*$. The results of the consumer preferences test showed that the darker colors of heat-treated woods were more preferred by consumers compared to the lighter colors of untreated woods. Consequently, heat treatment could enhance the color properties of Korean white pine and royal paulownia woods for value added products.

• 대한치과기공학회지
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• 제33권4호
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• pp.313-321
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• 2011

Purpose: The purpose of this study was to compare color parameters of different fabrication method of Lava ceram powder, Lava DVS blocks, IPS e.max ceram and IPS e.max zirpress. Methods: The three available shades(A1, A2, A3.5) of Lava & Kavo zirconia blocks were examined. For each of three colors, three different thickness were tested, 5 times of measurement frequency. The measurements were made using a spectrophotometer equipped with an integrating sphere using the CIE $L^*$, $a^*$, $b^*$ colorimetric system. Results: Lava build-up group and Lava DVS group showed clinically perceived color difference, on the other hand IPS e.max build-up group and IPS e.max zirpress group did not show clinically perceived color difference to shade allowed on core. When the thickness of porcelain veneer increased from Lava and IPS e.max groups, color differences(${\Delta}E$) were decreased. Conclusion: All-ceramic system has color characteristics that clinicians have to consider when selecting materials. Also, manufacturers of different porcelain systems must make every effort to achieve color reproducibility.

• 한국자원식물학회지
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• 제23권6호
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• pp.541-549
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• 2010

The present study researched morphological characteristics and analyzed the genetic diversity by using RAPD in Calanthe species, native plant in Jeju, Korea. Twenty-six samples were selected by flower color, and 19 horticultural traits were investigated to study morphological characteristics. The C. discolor had the smallest leaf, the length and width of dorsal sepal, lateral sepal, petal, central lip, lateral lip, and flower stalk length were shortest and/or smallest except the spur and ovary length in Calanthe species, but those of Calanthe discolor for. sieboldii (Dence.) Ohwi (Calanthe discolor for. sieboldii) were the largest and/or biggest, and those of variants were the intermediate between C. discolor and C. discolor for. sieboldii, but spur length was the longest in C. discolor, the shortest in C. discolor for. sieboldii, and intermediate in the variants. Ovary length in C. discolor was shortest and C. discolor for. sieboldii and variants were similar with each other. The flower colors of C. discolor were brownish red, the value of CIE Lab was between 40 and 50. The flower color of C. discolor for. sieboldii was yellowish; the value of CIE Lab was between 110 and 130. And variants had various colors between 50 and 70 in the value of CIE Lab. After analyzing multiple band patterns of PCR products, 154 bands were selected as polymorphic RAPD markers. The analysis of Genetic distance of Calanthe species using RAPD showed that C. discolor and C. discolor for. sieboldii are more distant from each other than variants, and demonstrated the fact that genetic position of variants is between the other two species.

• 한국의상디자인학회지
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• 제19권1호
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• pp.135-145
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• 2017

In order to analysis on color difference of yellow natural dyes, I have dyed cellulose and protein fabrics. The results of experiment have been analysed by wavelength of maximum absorption, amounts of dye uptake, color difference, Hunter's value and Munsell's value. The results from these analyses are as follows : Bud of pagoda tree, Amur cork, and Curcuma showed greenish yellow color, Gardenia Jasminoides showed reddish yellow color. Barberry root showed reddish yellow color with post-mordanting method on cellulose fabric. Moreover, Dupioni silk was dyed in reddish yellow color by Barberry root and Rhubarb. In addition to Chroma index, Gardenia Jasminoides and Curcuma showed clear color overall. However, dyeing rayon and silk by Barberry root, and dyeing silk by Rhubarb showed clear color. Comparing all the results to actual dyed materials, Bud of pagoda tree had small dye uptake, and both ${\Delta}a$ and ${\Delta}b$ value were short which can't recognized the yellow color easily. Dye uptake of Amur cork and Gardenia Jasminoides was small just like Bud of pagoda tree. However, ${\Delta}b$ value order was Gardenia Jasminoides>Amur cork>Bud of pagoda tree. Therefore, Gardenia Jasminoides recognized reddish yellow because of big value of red color and yellow color. In case of Barberry root and Rhubarb which have larger dye uptake, Baberry root recognized yellow color on rayon only, and couldn't recognized yellow color on bleached cotton fabric, ramie, silk, and dupioni silk. Rhubarb recognized yellow color on rayon with pre-mordanting method only, but recognized silk and dupioni silk as brown like color. Moreover, we could not analyze color by dye uptake, Lab, and H(v/c) for Barberry root and Rhubarb. As a result, I think we need to attach color table for the research paper which handled the color of dyeing materials.

• 한국가구학회지
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• 제19권6호
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• pp.460-465
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• 2008

When wood is exposed to natural weathering and UV radiation discoloration progresses. The color variation of heat-treated wood was investigated. Four domestic species were selected and heat-treated at $220^{\circ}C$ and naturally weathered for 42 days. Their colors were measured with a portable colorimeter. The color variations were different between species. The Korean red pine specimens were highly discolored by the natural weathering even though they were heat-treated. In contrast to Korean red pine, Korean pine is less discolored. The maximum color difference of larch was lower than Korean red pine. All specimens of birch exceeded the color difference criterion of 15 after 25 hours with the maximum of 28.

• 대한치과기공학회지
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• 제30권1호
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• pp.33-39
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• 2008

Recently natural characteristics and esthetics have been interested increasing in clinical dentistry. Thus the evaluation of the shade of dental porcelain has become an important part in dental research. Noritake Super Porcelain EX-3 Vita shade A2 (Noritake, Japan) Vintage HaLo Vita shade A2 (Shofu, Japan), Vita omega 900 Vitapan 3D-master shade 2M2 (Vita, Germany) were conducted for six times for repeated firing in a way to observe the change of color with respect to the number of firing. The repeated firing was implemented with the vacuum firing and air firing, and by using Shade Eye-EX Chroma meter (Shofu, U.S.A.), the changes in values of shade, value and chroma were compared. With the above results, the change of color was not noticed only in Vita when repeated firing was applied.

• 한국의류산업학회지
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• 제7권5호
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• pp.542-546
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• 2005

This study was investigated to establish the optimum conditions of dyeing silk fabric with Brassica campestris. This experiment was done under different dyeing conditions of dye concentration, dyeing temperature, dyeing time, dyeing repeating times, and mordants which were treated pre, syn, and post methods. The effects of dyeing conditions and mordanting were evaluated in terms of dyeaffinity(K/S value) and CIE-Lab color factors. Also, the effect of mordanting on color fastnesses was assessed. The dyeaffinity increased remarkably as dye concentration increased up to 200% owf. The dyeaffinity increased continuously with dyed temperature and reached dyeing equilibrium at $80^{\circ}C$. The maximum dyeaffinity was observed at 30minutes of dyeing time. In the relationship between the K/S value and dyeing repeating times, the K/S value became higher as repeating time was increased. The changes of surface color and colorfatness of dyes were not increased greatly on all mordanting states. The extracts of Brassica campestris produced mainly yellow color in silk fabric. The antimicrobial activity existed slightly as the ratio of 22.7%.