• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.10-16
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• 1999

Leaves harvested were separated with visual characters into 2 classes such as immature and mature leaves. In the curing process, the prolonged yellowing treatment during yellowing stage was automatically controlled at the different stalk position, and condition of curing process after this period was all the same with conventional ones. In case of prolonged yellowing in immature leaves, increase of price per kg reached to 8 % compared with those of conventional ones. In physical properties, filling capacity and shatter index was decreased with the degree of maturity, and it was equal level in filling capacity of immature leaves between curing method, while shatter index was decreased in prolonged yellowing treatment than that of conventional ones. There was no difference in chemical components between immature leaves of prolonged yellowing and conventional ones. As to the prolonged yellowing of immature leaves, there was decreased in citric and malic acid contents of the nonvolatile organic acids, and it was equal level in all higher fatty acids content of leaves cured by prolonged yellowing treatment compared with in that of conventional curing method. The contents of key compounds such as solanone, damascenone, damascone in the essential oil were lower in prolonged yellowing of immature leaves than those of mature leaves cured by conventional ones.

• Journal of the Korean Home Economics Association
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• v.35 no.2
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• pp.137-145
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• 1997

The effect of accumulated residual soils in wear and wash tests on yellowing of white dress shirt was studied. The test samples after repeated home laundry at 20 households for six months were measured residual soils, $\Delta$b*.As well as, correlation between residual soils and yellowing was also examined. As a result, residual soils increased with number of wear and wash cycles, a little decreased in using with enzyme detergent. The b* value of test samples with fluorescent whitening agent were distributed -12.850~0.291. Correlation coefficient between sebum soils, protein soils and $\Delta$b* was 0.98, 0.58. Ultimately, residual sebum soils have more higher correlation than residual protein soils. Hence, residual sebum soils have more effect on yellowing than residual protein soils. therefore, effective a device as improvement of laundry condition and textile development needs for decrease of sebum soils.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.2
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• pp.129-139
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• 1985

cent was carried out to study on the effect of temperature and humidity to chemical tobacco leaves during the yellowing stage. The results were follows : In the condition of high humidity and low temperature, yellowing time was delayed ; leaf color appeared lack clearness. In the higher temperature and the lower humidity during the yellowing stage : total sugar, reducing sugar and malic acid content were increased. Decomposition of nitrogenous components elevated in $38^{\circ}C$, 85%RH. Changes of total nitrogen content correlated with total curing time. Adecrease of linolenic acid with a corresponding increase of chlorogenic acid proceeded in the condition of low temperature and high humidity. In a view of tobacco quality by chemical components, the low temperature and high humidity during the yellowing stage decreased quality of tobacco leaves. It is considered to control of the proper condition of temperature and humidity during the yellowing.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.337-347
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• 2006

Papers made from unbleached and bleached bagasse chemimechanical pulp were chemically modified by acetylation. The effects of irradiation on unbleached and bleached also reduced papers of bagasse chemimechanical pulp before and after acetylation were investigated in this study. Chemimechanical pulp was prepared from bagasse and then bleached with hydrogen peroxide. Unbleached and hydrogen bleached pulps were reduced by Sodium borohydride in different procedures. Paper sheets were prepared from pulps and then acetylated using a technical grade of acetic anhydride. Accelerated photo-aging was run on the samples using fluorescent lamps to verify photo-stability of paper sheets before and after pretreatments. Brightness reversion (as Post-color number) and other optical properties of the paper sheets were measured. Efficient inhibition of photo-yellowing of papers made from bagasse CMP was achieved by acetylation. The acetylated unbleached CMP was noticeably photo-bleached during irradiation. Sodium borohydride reduction followed by acetylation had the same effect as acetylation alone at the same degree of reaction time and reductive treatment did not affect the yellowing rate to any great extent. The pre-reduced, acetylated unbleached papers were, however, not brightened during irradiation. Calculation done by Kubelka-Munk equation showed that reductive treatment had little effect in reducing the photo-yellowing of paper made from CMP pulp; a small stabilization effect was observed in the case of bleached CMP, while unbleached CMP was slightly more prone to discolor in the later phase of photo-reversion. The improved stability towards light may was closely related to the decrease in the phenolic hydroxyl content as a result of blocking by acetyl groups during treatment with acetic anhydride. The results support the hypothesis that phenolic hydroxyl has an important role in the process of photo-reversion of high-yield pulps. The results obtained in this study demonstrate that the acetylation of paper manufactured from peroxide bleached Bagasse CMP significantly retards light-induced discoloration. The inhibition of yellowing is connected with a decrease in the phenolic hydroxyl content of both unbleached and peroxide bleached papers.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.6
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• pp.909-918
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• 1999

The indigo-dyed blue denim garments are favored not only by young people but also by almost everyone of life, In the early years they were casually worn on most occasions but became universal recently. Such denim garments are treated with various process to give it optimal softness and color contrast of blue and white. The processess can generate photoyellowing and thus the yellowing may damage their appearance and quality. So this study is to find the solutions to reduce the photoyellowing problem. For this prupose sample denim were treated with cellulase fluorescent brightener UV absorbent etc. The results were as follows; The yellowing would be more accelerated by fluorescent brightening. Since the yellowing was reduced by 90% In particular the application of the UV absorbent before using of the fluorescent brightener was most effective. The optimal concentration was 0.5% (o.w.f) and the benzophenone compounds were found most effective for the indigo denim. And reduction effect of yellowing by UV absorbent was lowered with repeated laundering but metal compound treatment on fabric made a removal of UV absorbent by laundering prevented.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 1998.10a
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• pp.15-15
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• 1998

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.111-119
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• 1976

Discoloration of canned boiled oyster namely greening, yellowing and browning often occur separately or associatively in the storage of the product. Greening is mainly caused by the appearance of chlorophyll and its derivatives on the surface around the digestive diverticula of the oyster and yellowing by dispersion of carotenoid. Browning reactions by sugar amino condensation or enzymatic action, tyrosinase, also cause an undesirable color development. In this paper, the stability and the changes in distributional or partitional ratio of chlorophyll and carotenoid pigment of meat vs viscera in raw and canned oyster during six month storage in order to measure the dispersion rate of both pigments between meat and viscera, and to evaluate the feasibility of discoloration of oyster meat. The development of brownish pigment and the toss of free tyrosine in oyster were also determined to compare the readiness of color development. In addition the influence of processing and storage conditions to the dispersion rate and the tendency of discoloration, and finally the effect of inhibitor were discussed. The results showed that greening or yellowing was initiated by the dispersion of chlorophyll or carotenoids from viscera to the meat of oyster, and the dispersion rate of carotenoid was much higher than the chlorophyll's, so that, yellowing appeared a leading reaction of discoloration. The dispersion rate was obviously fastened by raising the temperature in the process of sterilization and storage. Consequently, the low temperature storage could largely retard the occurance of yellowing or greening of oyster meat. The pH control of canned oyster did not seem to affect the dispersion of pigment but significantly did on the stability of the piqments. Browning by the reaction of sugar-amino condensation and enzymatic oxidation of tyrosine was positively detected in canned oyster meat. The development of brownish color was influenced rather by the storage temperature than the heating process. Addition of sodium sulfite in can or treating the boiled oyster with sulfite solution prior to filling seemed possibly inhibit the color development particularly in cold-storaged oyster meat.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.344-349
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• 2013

This paper proposes a simulation algorithm to assess the gradual yellowing vision of the elderly, which refers to the predominance of yellowness in their vision due to aging of the ocular optic media. This algorithm employed the spectral transmittance property of a yellow filter to represent the color appearance perceived by elderly people with yellow vision, and modeled the changes in the color space through a spectrum change in light using the yellow filter effect. The spectral reflectivity data of 1269 Munsell matte color chips were used as reference data. Under the standard conditions of a D65 illuminant and a $10^{\circ}$ observer of 1964 CIE, the spectrum of the 1269 Munsell colors were processed through the yellow filter effect to simulate yellow vision. Various degrees of yellow vision were modeled according to the transmittance percentage of the yellow filter. The color differences before and after the yellow filter effect were calculated using the DE2000 formula, and the color pairs were selected based on the color difference function. These color pairs are distinguishable through normal vision, but the color difference diminishes as the degree of yellow vision increases. Assuming 80% of yellow vision effect, 17 color pairs out of $(1269{\times}1268)/2$ pairs were selected, and for the 90% of yellow vision effect, only 3 color pairs were selected. The result of this study can be utilized for the diagnosis system of gradual yellow vision, making various types of test charts with selected color pairs.

• Journal of Conservation Science
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• v.30 no.2
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• pp.181-187
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• 2014

AThe studies on ceramic preservation have been conducted widely in various institutions such as national/ public museums and research labs as well as the excavation institutions and university museums. Although there are some differences in preservation methodologies and materials used across the institutions, the variation is minimal. Specifically, epoxy resin is mostly used for ceramic restoration for its high cohesiveness, low contraction and high strength although there are some variations in for Ceramic Preservation. The synthetic resin type used according to the type of damage in the ceramic. However, the yellowing or the change of color across the time after the restoration is the weakness of epoxy resin. In this study, we aim to develop a material which minimizes this yellowing of epoxy resin while enhancing its cohesiveness and strength as well as other physical properties. We made the new material to have similar properties with those used widely for the ceramic restoration, such as EPO-TEK301$^{(R)}$, L30$^{(R)}$, XTR-311$^{(R)}$ through comparative experiments. The cohesiveness of the newly developed resin was improved to 2.51(MPa), which is similar level of XTR-311$^{(R)}$ of the 2.30(MPa) but about 2x higher than the other resins EPO-TEK301$^{(R)}$, L30$^{(R)}$ (1.21 and 1.81 (MPa), respectively). Especially, the experiment on yellowing shows that the existing resins show the range of color change at 10~25(${\Delta}E^*ab$), but the new low yellowing epoxy resin has the color change value at 8.3 (${\Delta}E^*ab$), the value lowering the yellowing effect to 1 to 3 times of the existing epoxy resin, thereby solving the issue of generating sense of differences due to change of color or yellowing.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.2
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• pp.9-15
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• 1983

The effect of leaf dehydration process and air flow capacity of bulk curing on physical properties and composition of cured leaves was studied, respectively, during flue- curing. Cured leaves from excessive moisture during yellowing stage and those from rapid dehydration Process inevitably during later stages, tend towards lower equilibrium moisture contents, higher shatter index, hither protein nitrogen, and leaf scalding or deterioration of Beaves with redish cast. Early dehydration at the yellowing stage re suited in increasing of p Bamitic, stearic, linoleic, and linolenic acid contents, but showed reduction of brightness difference between upper and lower surface of the cured leaves, Leaf surface lipid decreased with the progress of curing stages, more conspicuously during later stage. Lowering air flow capacity of fan by 50oye during stem drying stage resulted in increasing of leaf surface lipid and 25oye decreasing of electric power consumption , but curing period and kerosene consumption were not affected.