• 한국의류산업학회지
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• 제4권2호
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• pp.198-202
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• 2002

Degummed silk from Bombyx mori was dissolved in 9.3M lithium bromide solution. The regenerated silk fibroin films were completely ${\alpha}$-randomcoil type as shown by x-ray diffraction and infrared spectroscopy. The structural changes in silk fibroin induced by immersion into methanol and dilute hydrochloric acid and its photo-yellowing effect was studied. The changes of crystallinity were measured by infrared spectrometer. Yellowness index caused by ultraviolet irradiation were observed as a function of the structural change on silk fibroin. On treatment with methanol, ${\alpha}$-randomcoil silk film is converted to the ${\beta}$-form structure. After the treatment of hydrochloric acid on ${\beta}$-form structure in silk induced by immersion into methanol, ${\beta}$-form in silk fibroin is partially decreased. Crystallization owing to ${\beta}$-form transition reduced the initial yellowness index by ultraviolet irradiation. A little ${\beta}$-form structure in silk fibroin increased the initial yellowness in comparison with more ${\beta}$-form structure.

• Current Photovoltaic Research
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• 제6권3호
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• pp.81-85
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• 2018

The photovoltaic modules installed in the actual field are affected by various external environments and the electrical performance output value is generally lowered compared to initial output value. The most of photovoltaic modules consists of low iron glass, encapsulant (EVA), back sheet, frame and junction box assembly based on the solar cells. In this paper, the characteristics of encapsulant which is an important constituent material of photovoltaic module were verified by maximum power determination, electro luminescence images, yellowness index measurement, and gel content measurement after ultraviolet (UV) irradiation exposure. The most commonly installed 72 cells crystalline photovoltaic modules were tested after various UV exposure of 0, 15, 30, and $60kWh/m^2$ and compared with the reference module. After UV exposure of $15kWh/m^2$, which is the current international test condition, a small amount of change was observed in yellowness index and electroluminescence, while a gell content rapidly increased. At a cumulative dose of $60kWh/m^2$, which will be a new international test condition in the near future, however, the yellowness index increased sharply and showed the greatest output power drop.

• 한국염색가공학회지
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• 제25권4호
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• pp.241-246
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• 2013

The color properties of a white or nearly colorless fabric are represented by whiteness index (WI) or yellowness index (YI). These two indexes relate to a white fabric's color quality. The purpose of this study was to identify the properties of WI and YI on the CIELAB through the simulations of estimation data for a systemization of color quality control. The results indicated that the relationship between WI and YI was a negative correlation, however the coefficients of correlation function between WI and YI were depended on hue. There were two hue transition points of the rate of changes in WI and YI. These hue transition points were the reference points to divide the hue contribution to WI and YI. These points were not the point of h=0 and h=180 and asymmetric. In addition, where the colors were same distance from the white point on the CIELAB, the rate of changes in WI and YI by ${\Delta}$Ew were depending on hue. Specifically, when WI decreased, YI of reddish and yellowish tinted colors decreased more than bluish tinted colors.

• 한국염색가공학회지
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• 제6권2호
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• pp.24-29
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• 1994

In order to investigate the crystallization in silk fibroin induced by acid treatment and its photo-yellowing reduction effect. silk fibroin were immersed in PH 3.5~4.0 sulfuric acid and 0.01N hydro-chloric acid at 2$0^{\circ}C$, and the changes of crystallinity were measured by infrared spectroscopy, X-ray diffraction. Yellowness index caused by UV irradiation were also observed. The results are as follows : 1. ${\beta}$-form transition occurs when the silk fibroin are immersed at 2$0^{\circ}C$ in pH 3.5~4.0 sulfuric acid and 0.01N hydro-chloric acid. Formation of new hydrogenbond in molecules on the amorphous region induced ${\beta}$-form structure, and increased crystallinity. 2. Crystallization owing to $\beta$-form transition reduced the initial yellowness index by ultraviolet irradiation.

• 한국의류산업학회지
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• 제3권4호
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• pp.373-377
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• 2001

When the polyester/cellulosic fiber mixed fabrics were treated with sodium hydrogensulfate for burn-out printing, it is examined how the effects of process conditions as concentration of acid, fixation temperature and fixation time act onto the properties of the polyester ground fabrics. The print paste, indalca solution, was mixed with sodium hydrogensulfate and glycerine, and then screen-printed on the fabrics. The properties of the polyester ground fabrics after removing away the cellulosic fibers were investigated. The yellowness index and the breaking load of polyester ground fabrics affected by the process conditions, especially dry heat fixation temperature.

• 한국의류학회지
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• 제23권5호
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• pp.757-763
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• 1999

The burn-out technique is used to result in the velvet cloth being patterned in open and solid areas by carbonize the cellulose fiber. It is examined how to burn out the cellulose part of the velvet without damage of the other part. The print paste indalca solution is mixed with sodium hydrogensulfate and lycerine and then screen-printed on the back side of the velvet. The effects of process conditions such as concentration of sodium hydrogensulfate dry heat fixation temperature and time pull no. and glycerine contents on the properties of ground farics were investigated. The yellowness index and the breaking load of silk ground fabrics afected by the process conditions especially concentration of sodium hydrogensulfate dry heat fixation temperature.

• Macromolecular Research
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• 제17권6호
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• pp.411-416
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• 2009

The color stabilization of antimicrobial blends was studied by using poly(hexamethylene guanidine) phosphate (PHMG) as a highly efficient biocidal and nontoxic agent. The Taguchi method was used to determine the optimum conditions for the blending of PHMG in polypropylene (PP) matrix. To improve the yellowing phenomena, two kinds of stabilizer were used together: tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)](IN1010) from phenol and tris(2,4-di-t-butylphenylphosphite) (IF168) from phosphorus. According to blend composition and mixing condition, six factors were chosen, with five levels being set for each factor. The orthogonal array was selected as the most suitable for fabricating the experimental design, L25, with 6 columns and 25 variations. The-smaller-the-better was used as an optimization criterion. The optimum conditions for these parameters were 10 phr for PHMG, 2 phr for IN1010, 1 phr for IF168, 10 min for mixing time, $210^{\circ}C$ for mixing temperature, and 30 rpm for rotation speed. Under these conditions, the yellowness index of the blend was 1.52. The processibility of the blends was investigated by Advanced Rheometric Expansion System (ARES). The blend with 0.5 w% PHMG content, diluted with PP, exhibited an antimicrobial characteristic in the shake flask method.

• Fibers and Polymers
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• 제4권3호
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• pp.124-128
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• 2003

Dark brown Alpaca fiber was reduced in shade via selective bleaching with peroxide. Two selective oxidative bleaching methods were tested on alpaca top to assess their effectiveness for color removal and fiber quality properties. Color change, bundle strength, weight loss, fiber diameter, surface modification, dye-ability and dye wash fastness were assessed for both methods and compared with the original brown top. Bleach method 1 (BL-I) showed little surface modification, 5.8% weight loss and 2.4% strength loss. D1925 yellowness index was reduced to 74.3 from 83.1 and provided a good base for the dyeing of medium to deep shades. Bleach method 2 (BL-II) displayed considerable surface modification, 7.8% weight loss and 18% strength loss. BL-II also resulted in a mean diameter reduction of 1.9 micron during bleaching. Yellowness was reduced to 64.5 from 83.1 and provided a very good base for the dyeing of medium to deep shades. BL-I showed better exhaustion of the premetallised dye Lanaset Violet B than BL-II. Wash fastness for BL-II was 1 grey scale unit poorer than BL-I. BL-II showed far better color clarity at pale depths however the wash fastness of the finished product was not good enough to maintain the depth or clarity of the color. BL-I showed poorer clarity of color but exhibited better wash fastness results.

• 한국의류학회지
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• 제18권4호
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• pp.549-559
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• 1994

The purpose of this study was to study accumlated residual soils which may be one of the causes for yellowing of worn cloths. Wear and wash tests of white cotton undershirts were repeated at 30 households sellected at random over a period of 60 days. Laundry conditions were similar to home laundry habits in a fact-finding survey, using a powdery heavy duty detergent containing no enzymes or enzymes. The subjects in this study were survey of laundry actual condition, the undershirts from prior to and after the final washing was measured residual soils, $L^*a^*b^*$ value and mellowness index of CIE system. D3ta were analysed by simple correlation analysis of wear and wash cycle, residual soils, whiteness The results obtained were summarized as follows: 1. Using pattern of washing machine, Presoaking was no singinificant differnece in general characteristics of survey respondent. Laundry frequency was significant difference in income level, occupation of housewives whether or not. Use of cold and hot water was significant difference in residence shape. 2. The analyzed consequences of recognition and actual behavior in connection with laundry were found variables each other to have independence or not. 3. Amount of residual sebum soils is using non-enzyme detergent were much more than in using enzyme detergent, increased linearly with increase of the number of wear and wash cycles. 4. Residual protein soils with increase of the number wear and wash cycles less than in laundering more easy than sebum soils. Since accumulated residual sebum soils were much more than residual protein soils. 5. Increase of residual soils was raised mellowness index and diminshed whiteness. yellowness index of residual sebum soils was higher than protein soils. If increase of whiteness will be incresed, amount of residual sebum soils will be decreased sebum soils. Because amount of residual sebum soils much more than protein soils, yellowness index of residual sebum soils was more higher than that of protein soils.

• 펄프종이기술
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• 제43권2호
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• pp.57-65
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• 2011

Pulping of paper mulberry (Broussonetia kazinoki) white bast has been examined by novel atmospheric pressure pulping methods. The viscosity of pulp has been found to be highly sensitive and variable with pulping methods. Therefore, selections of pulping chemicals and conditions are very important. Two kinds of pulping procedures were employed for the high viscosity pulp manufacturing. The one is ammonium oxalate treatment and the other is sodium chlorite and acetic acid treatment. Not only chemical components and pulp yields which of paper mulberry white bast but also water retention value (WRV), whiteness index, yellowness index, and colors of every pulp were examined. The hot water, 1% NaOH, and ethanol-benzene extractives which of paper mulberry white bast were 4.48%, 28.45%, and 2.84%, respectively. The contents of holocellulose, lignin, and ash were 90.66%, 1.05%, and 2.18%, respectively. In the pulp yields, group 1 which treated with only ammonium oxalate were 77.04-81.71%, group 2 which treated with ammonium oxalate and acidified sodium chlorite separately and washed between first and second stages were 64.15-83.90%, group 3 which treated with ammonium oxalate and acidified sodium chlorite separately and not washed between first and second stages were 57.35-73.17%, and group 4 which treated with mixed ammonium oxalate and acidified sodium chlorite were 66.58-68.43%. The pulps treated with acidified sodium chlorite showed high whiteness index, but the pulps treated with only ammonium oxalate showed high yellowness index. Variations in the combinations of treatments resulted in different pulp characteristics.