• Journal of Applied Reliability
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• v.7 no.4
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• pp.173-181
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• 2007

Out door exposure to daylight and weather climate conditions can cause adverse effect on the properties of automotive plastic materials. The effects of sunlight exposure, especially ultra violet (UV) radiation, can break down the chemical bonds in a polymeric material. This degradation process is called photo-degradation and ultimately leads to color changes, cracking, chalking, the loss of physical properties and deterioration of other properties. To explore the effect of sunlight exposure on the automotive materials, this study investigated photo-oxidation degree and surface property change of molding parts by analytical methods. For the further study, accelerated weathering test methods are proposed, which can correlate with out door weathering, to predict long term performance of automotive plastic materials.

• Molecules and Cells
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• v.38 no.5
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• pp.390-395
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• 2015

Degradation of chlorophyll (Chl) by Chl catabolic enzymes (CCEs) causes the loss of green color that typically occurs during senescence of leaves. In addition to CCEs, STAYGREEN1 (SGR1) functions as a key regulator of Chl degradation. Although sgr1 mutants in many plant species exhibit a staygreen phenotype, the biochemical function of the SGR1 protein remains elusive. Many recent studies have examined the physiological and molecular roles of SGR1 and its homologs (SGR2 and SGR-LIKE) in Chl metabolism, finding that these proteins have different roles in different species. In this review, we summarize the recent studies on SGR and discuss the most likely functions of SGR homologs.

• Journal of Applied Biological Chemistry
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• v.50 no.4
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• pp.221-226
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• 2007

The high molecular-weight mucilage extracted and purified from cactus fruit of Opuntia ficus-indica var. Saboten was degraded by the cell-free culture filtrate of a fungus isolated from soil. TLC analysis of the polymeric mucilage after incubation with the fungal culture filtrate confirmed its degradation. When the degradation products were tested for their qualitative reactions with ninhydrin and phenol-sulfuric acid, only phenol-sulfuric acid gave positive development, and ninhydrin did not show any observable color reaction. This coloring reaction suggested the presence of a carbohydrate without an amino group within the mucilage. Analyses by HPLC and liquid gel permeation chromatography on sephadex G-100 also provided additional information on degradation of the mucilage by the fungal culture filtrate. The sequences of ITS-5.8S rDNA from the fungal isolate that was cultivated for the preparation of mucilage-degrading enzyme showed 99% similarity to those of Pestalotiopsis aquatica.

• Preventive Nutrition and Food Science
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• v.9 no.4
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• pp.295-299
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• 2004

Alpha-tocopherol was thermally oxidized and degraded at high temperatures and the resulting products were chromatographically separated and identified by LC-MS. Alpha-tocopherol dissolved in glycerol was heated at 200^{\circ}C for 30 min. The thermal products were separated by hexane extraction and analyzed by HPLC using a reversed phase $\mu$-Bondapak $C_{18}-column$ with two kinds of elution solvents: a mixture of acetonitrile and methanol (3:2), and of acetonitrile, methanol, 2-propanol, chloroform and methylene chloride (3:2:5:0.5:0.5) in a gradient mode. The isolated thermal. products of alpha-tocopherol were more viscous than alpha-tocopherol, and dark brown in color. Major thermal degradation products of alpha-tocopherol were identified by LC-MS, and the structures of thermal products were proposed. Alpha-tocopherol and its thermal degradation products were degraded into fragments, mainly at the non-aromatic parts. The degradation products of alpha-tocopherol. were combined with oxidized product (tocopherylquinone) to make thermal. products through dimerization.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.5-8
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• 2012

Haze is an extreme reason of the reduction of contrast when capturing image in the outdoor. Recently, there are several single image dehazing techniques, but they are not robust in dynamic variations of natural environment caused by the thickness, coverage of haze and appearance of sunlight. In this paper, we propose an effective and robust method to restore degradation of hazy image. Compare with conventional methods, our proposal have better performance and computation time.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.733-736
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• 2006

In the many kind of construct-material, the concrete which has the high-strength and a durability is sufficient to use with structure-material. But the color of concrete is very monotony so generally concrete isn't used the out surface. although color concrete is a method of expressing surface, the combination of pigment and cement cause many Physical problem such as efflorescence phenomenon, strength degradation and so on. In this study, It attempt to develop the black mortar using the industrial by-product and to evaluate basic physical properties compare with general color concrete to solve the color concrete problem. The result of experiment showed that Black NSC which was made by-product has more visible black color than any mortar.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.3
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• pp.311-318
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• 2016

This paper shows storage life estimation of next IR(infrared) flare material through accelerated degradation tests. Three temperature conditions for the accelerated degradation tests are 55, 65 and $75^{\circ}C$. Six performances of IR flare material are burning time, IR peak/continuous Intensity, total energy of near/mid-IR and color ratio, and they were measured after the tests. Storage life of the IR flare material was estimated through both analyzing the degradation data of those performances and applying distribution-based degradation models to the data. Over 30 years of storage life at $20^{\circ}C$ is estimated in terms of IR peak intensity with reliability 0.99 and confidence level 99 %. Additionally, 10 years of storage period at $21^{\circ}C$ would be equivalent to 68 days of accelerated test at $65^{\circ}C$ from the activation energy in Arrhenius model.

• Journal of Conservation Science
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• v.32 no.4
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• pp.491-500
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• 2016

Fog is atmospheric in which tiny drops of water vapor are suspended in the air near the ground. Its form, occurrence, etc., change according to the temperature, relative humidity, wind and geographical features of the space around it. In particular, fog tends to occur near a source of water because of temperature and relative humidity difference. These days, climate change is increasingly affecting the occurrence of fog. Therefore the purpose of this study was to investigate how fog affects materials that are part of our cultural properties through outdoor exposure tests and artificial degradation. The degradation evaluation of materials as a function of fog occurrence frequency, showed that the color of metals changed noticeably, whereas dyed silk and Dancheong showed degradation on the surface and color differences but no particular tendencies. Therefore, damage prediction by color differences as a function of fog occurrence frequency was based on metal samples, which showed constant color differences. Through a comparison of the predictive value and color difference by outdoor exposure, the accuracy and applicability of the damage prediction formula was confirmed. If a more complex damage prediction formula is created, it is expected that prediction of the degree of material damage in the field would be possible.

• Journal of Conservation Science
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• v.33 no.6
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• pp.553-564
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• 2017

This report compared and analyzed the degree of surface change and results of a deterioration experiment to assess the possibility of using Dobak glue as an adhesive in the fossilizing treatment of the paint layer in earthen mural paintings. The weathering experiments were performed with a color-difference meter (CR-400, MINOLTA). After the experiment, Cinnabar 3% specimens, which exhibited diverse changes in the durability test, were additionally tested with a reflection-transmission device (CARY-5000, AGILENT). Post UV degradation, most of the Dobak-glue samples exhibited lesser color change than animal-glue samples, and after moisture absorption and drying, the 0.5% and 3% Dobak samples displayed a lower degree of change in the value of color difference. Furthermore, results of the reflection-transmission test after deterioration indicated that Dobak glue presented a lesser color change than animal glue. Therefore, if Dobak glue is used as a consolidating agent, discoloration on account of degradation is minimal.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.754-759
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• 2011

Zinc protoporphyrin (ZnPP) is produced endogenously during heme metabolism and treated in cells as a heme oxygenase inhibitor. In the present study, the effects of ZnPP on the color response of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a commonly-used method for analyzing cell viability, were investigated. ZnPP induced rapid decolorizaion of MTT formazan under light; the degradation rates were 10- and 20- folds faster in the presence of 5 and $10{\mu}M$ ZnPP, respectively. Methylene blue (MB), another type of photosensitizer, also accelerated degradation of formazan under light. Butylated hyroxytoluene did not inhibit ZnPP- or MB-induced formazan degradation. The color degradation of formazan dye was signficantly delayed in the presence of N-acetylcysteine or ${\beta}$-carotene. The present results suggest that certain photosensitizing compounds may affect the color and stability of MTT formazan, which should be carefully considered when conducting the MTT assay.