• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.127-135
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• 1999

Nickel oxide films were prepard by using the electron beam evaporation technique. Coloring and bleaching experiments for cyclic durability were repeated in KOH electrolyte by cyclic voltammetry. Visible spectrophtometry was used to assess the stability of the transmittance in the degraded films. X-ray photoelectron spectroscopy results showed that the grain surface are oxygen-rich compared to the grain interiors in a NiO film. Open circuit memory of colored films is about 400hours in lN KOH. The rate of self discharge was evaluated by measuring the transmittance at 550nm of a fully oxidized NiO film. The rate of self discharge was increased polynomially with time and the film is nearly bleached after about 400hours. It was also found that the degraded film by repeated cycles in the KOH solution changed the grain shape of film surface The film prepared under a vacuum pressure of $3\times10^{-4}$ mbar was found to be rather stable when subjected to the repeated coloring and bleaching cycles in KOH electrolyte. Band theory applied to explain the electrochromic mechanism was discussed.

• Textile Coloration and Finishing
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• v.5 no.4
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• pp.49-59
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• 1993

In order to study the bleaching of cotton fabrics, ozone which has been produced by an ozone generator, has been contacted with cotton fabrics in water at various conditions. The equipments used for the ozone treatment of cotton fabrics were the ozone generator and a liquor/ozone contactor. For the examination of the ozone bleaching effect on cotton fabrics the whiteness, tensile strength, wettability and clark softness of the ozone treated cotton fabrics were measured. The conclusion obtained were, ozone concentration was increased, as the voltage was increased and flow rate was decreased and oxygen amount was increased. Bleaching effect of treated fabrics increased with increasing attributed more the net concentration of ozone rather than the total ozone amount of produced. The whiteness of treated fabrics was found to be best when treating temperature was 15~20<$^{\circ}C$, in acidic condition. The tensile strength of treated fabrics decreased as the treating time increased, and as the temperature raised, and the acidity increased. The wicking distance of treated fabrics increased slightly with increasing the treating time and the temperature. Clark softness of treated fabrics was not changed until passing 30min. of the treating time, then it decreasing linealy with increasing the treating time.

• Proceedings of the Ginseng society Conference
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• 1990.06a
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• pp.49-57
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• 1990

It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifling and kaempferol from Ginseng leaves on single oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated . Each flavonoid aglycone (5-50UM) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging 102 and free radicals. Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by 1O2. The 102 and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by 1O2 and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micelle or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed. Keywords Panax ginseng C.A Meyer, ginseng leaves, flavonoids, singe1 oxygen, Photohemolysis.

• Journal of the Korean Wood Science and Technology
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• v.7 no.2
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• pp.3-30
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• 1979

Larch ($\underline{Larix}$ $\underline{leptolepis}$ GORDON), one of the major afforestation species in Korea in view of its growing stock and rate of growth, is not favored as a raw material for pulp due to its low yield of pulp and difficulties with bleaching arising from the high content of extractives in wood, and the high heartwood ratio and the active phenolics, respectively. The purpose of this study is to investigate the characteristics of firstly pulping with various additives of cellulose protector for the yield of pulp, and secondly bleaching with oxygen for chlotination-alkali extraction of five stage-sequence to reduce chlorine compounds in bleaching effluents. The kraft cooking liquor for five age groups of larchwood was 18 percent active alkali with 25 percent sulfidity and 5 : 1 liquor-to-wood ratio, and each soda liquor for sap-and heart-wood of the 15-year-old larchwood was 18 percent alkali having one of the following cellulose protectors as the additive; magnesium sulfate ($MgSO_4$, 2.5%), zinc sulfate ($ZnSO_4$, 2.5%), aluminium sulfate ($Al_2(SO_4)_3$, 2.5%), potasium iodide (KI, 2.5%), hydroquinone (HQ, 2.5%), anthraquinone (AQ, 0.1%) and ethylene diamine (EDA, 2.5%). Then each anthraquinone-soda liquor for the determination of suitable cooking condition was the active alkali level of 15, 17 and 19 percent with 1.0, 0.5 and 0.1 percent anthraquinone, respectively. The cooking procedure for the pulps was scheduled to heat to 170$^{\circ}C$ in 90 minutes and to cook 90 minutes at the maximum temperature. The anthraquinone-soda pulps from both heartwood and sapwood of 15-year-old larchwood prepared with 0.5 percent anthraquinone and 18 percent active alkali were bleached in a four-stage sequency of OCED. (O: oxygen bleaching, D: chlorine dioxide bleaching and E: alkali extraction). In the first stage oxygen in atmospheric pressure was applied to a 30 percent consistency of pulp with 0.1 percent magnesium oxide (MgO) and 3, 6, and 9 percent sodium hydroxide on oven dry base, and the bleached results were compared pulps bleached under the conventional CEDED (C: chlorination). The results in the study were summarized as follows: 1. The screened yield of larch kraft pulp did not differ from particular ages to age group, but heartwood ratio, basic density, fiber length and water-extractives contents of wood and the tear factor of the pulp increased with increasing the tree age. The total yield of the pulp decreased. 2. The yield of soda pulp with various chemicals for cellulose protection of the 15-year-old larchwood increased slightly more than that of pure soda pulp and was slightly lower than that of kraft pulp. The influence of cellulose protectors was similar to the yield of pulps from both sapwood and heartwood. The effective protectors among seven additives were KI, $MgSO_4$ and AQ, for which the yields of screened pulp was as high as that of kraft pulp. Considering the additive level of protector, the AQ was the most effective in improving the yield and the quality of pulp. 3. When the amount of AQ increased in soda cooking, the yield and the quality of the pulp increased but rejects in total yield increased with decreasing the amount of active alkali from 19 to 15 percent. The best proportion of the AQ seemed to be 0.5 percent at 17 percent active alkali in anthraquinone-soda pulping. 4. On the bleaching of the AQ-soda pulp at 30 percent consistency with oxygen of atomospheric pressure in the first stage of the ODED sequence, the more caustic soda added, the brighter bleached pulp was obtained, but more lignin-selective bleaching reagent in proportion to the oxygen was necessary to maintain the increased yield with the addition of anthraquinone. 5. In conclusion, the suitable pulping condition for larchwood to improve the yield and quality of the chemical pulp to the level for kraft pulp from conventional process seemed to be. A) the selection of young larchwood to prevent decreasing in yield and quality due to the accumulation extractives in old wood, B) the application of 0.5 percent anthraquinone to the conventional soda cooking of 18 percent active alkali, and followed, C) the bleaching of oxygen in atmospheric pressure on high consistency (30%) with 0.1 percent magnesium oxide in the first stage of the ODED sequence to reduce the content of chlorine compounds in effluent.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.75-83
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• 2001

The potential of oxygen delignification is a powerful tool to reduce detrimental environmental effects. This study was performed to investigate the effect of steam explosion treatment of chemically treated oak wood on oxygen-alkali pulping. Pulp yield during steam explosion treatment by ${Na_2}{O_3}$-NaOH impregnation was higher than the other impregnation chemicals. Also, NaOH extraction at room temperature after steam explosion treatment improved the kappa number from 140~116 to 90~64. Oxygen-alkali pulping of chemical steam explosion treated woods affected to pulp yields. ${Na_2}{O_3}$-NaOH impregnation was very effective to higher carbohydrate yields at same delignification level. Its carbohydrate yield seemed to be highly related to the effluent pH. Oxygen-alkali pulping after steam explosion treatment of ${Na_2}{O_3}$-NaOH impregnated wood was shown that carbohydrate yield was very high because its effluent pH was increase from natural to mild alkali. Even if oxygen bleaching limit the delignification to 50% in order to avoid unacceptable yield and viscosity losses, oxygen-alkali pulping after steam explosion by ${Na_2}{O_3}$-NaOH impregnation was possible to extend the delignification more than 80%. Considering high pulp yield with lower lignin content from steam explosion treated wood, it might be profitable to end the cook at a high kappa number instead of a low kappa number, and continuously apply the oxygen delignification, in order to better quality pulp.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.7 s.155
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• pp.1160-1167
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• 2006

The most ideal textile conservation is to block oxygen and light from historical textiles. However it is not possible because historical textiles should be examined, cleaned, restored, and exhibited to find out its historical value. Most of excavated costumes were severely stained and soiled. They are dark yellowish brown in color. To reduce the extent and intensity of the staining and to recover the original color of gray fabrics, bleaching would be required. Conservation treatment was carried out on the 8 historical costumes which belonged to General Duk-Ryung Kim(1567-1596). Two of them do not hold the fabrics. They hold only cotton wool and a little piece of fabrics. Even though these costumes underwent the conservation treatment in 1979, they were stained and needed re-treatment. This time, they were dual-bleached using hydrogen peroxide and sodiumborohydride followed by wet cleaning to reduce the soils and stains. The treatments improved the appearance of costumes. Through the analysis of the trace of fabric, carbonized fabric fragment, and fabrics remained in other garments, we concluded the missing fabrics to be ramie or cotton. It is different result from the primary report concluded to be silk.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.191-199
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• 1990

It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifolin and kaempferol from Ginseng leaves on singlet oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated. Each flavonoid aglycone (5-50$\mu$M) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging $^1O_2$ and free radicals Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by $^1O_2$. The $^1O_2$ and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by $^1O_2$ and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micells or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed.

• Resources Recycling
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• v.18 no.2
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• pp.16-29
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• 2009

This paper describes characteristics of pollutants in wastewater from the pulp and paper industry and biological technologies for the wastewater treatment. The wastewater from the pulp and paper industry contains high concentrations of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) and shows high toxicity and strong black-brown color. In particular, organic chlorinated compounds such as dioxins and furans may be formed by the chlorination of lignin in wood chips. Thus the pulp and paper industry is recently trending toward total chlorine-free (TCF) bleaching processes. All biological technologies for pulp and paper wastewater treatment are based on the contact between wastewater and bacteria, which feed on organic materials in the wastewater, thus they reduce BOD concentration in it. Both aerobic and anaerobic treatments were found to be effective for the wastewater treatment. Furthermore, advanced technologies such as fungal application and combined biological-filtration process have been also introduced to the wastewater treatment field. These technologies would be useful for water recycling to reduce water consumption throughout pulp and paper making process.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.45-51
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• 1989

A major problem in the enzymatic hydrolysis of lignocellulosic substrates is the very strong bonding of cellulase to lignin and even cellulose in the hydrolysis residues. This phenomenon inhibits recycle of the cellulase which is a major expense of the enzymatic hydrolysis process. In this paper, autohydrolyzed wood was delignified by two-stage with a 0.3% Na OH extraction and oxygen-alkali bleaching and was subjected to enzymatic hydrolysis with cellulase. Also, an improved almost quantitative recycle process of cellulase enzyme was discussed. In enzyme recovery by affinity method. the first recycling showed relatively high hydrolysis rate of 97.4%. Even at the third recycle. hydrolysis rate was 86.7 percents. In the case of cellulase recovery by ultrafiltration method, first 2 recycling treatments resulted very high hydrolysis rate(97.0-97.7%). Even the third recycling showed about 94.2%. Authoydrolysis of oak wood followed by 2-stage delignification with alkali and oxygen-alkali produced a substrate for enzymatic hydrolysis that allowed almost quantitative recycle of cellulase.

• Journal of the Korean Wood Science and Technology
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• v.19 no.1
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• pp.14-21
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• 1991

Steam-exploded woods were delignified by two-stage with a 0.3% NaOH extraction and oxygen-alkali bleaching and were subjected to the enzymatic hydrolysis with cellulase enzyme. Also, an improved almost quantitative recycle process of cellulase enzyme was discussed. In enzyme recovery by affinity method, The first recycling showed relatively high hydrolysis rate of 96.4%. Even at the third recycle, hydrolysis rate was 87.0 percents. In the case of cellulase recovery by ultrafiltration method, first 2 recycling treatments resulted in very high hydrolysis rates, 96.8% and 95.0%, respectively. Even the third recycling showed about 93.6%. Steam-explosion treatment of oak wood followed by 2-stage delignification with alkali and oxygen-alkali produced a excellant substrate for the enzymatic hydrolysis that allowed almost quantitative recycle of cellulase.