• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.231-244
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• 2020

As a way of finding value-added materials from waste medium density fiberboard (MDF), this study characterized cellulose nanocrystals (CNCs) isolated by ammonium persulfate (APS) oxidation using recycled MDF fibers. Chemical composition of the recycled MDF fibers was done to quantify α-cellulose, hemicellulose, lignin, nitrogen, ash and extractives. The APS oxidation was performed at 60 ℃ for 16 h, followed by ultrasonication, which resulted in a CNC yield of 11%. Transmission electron microscope images showed that rod-like CNCs had an average length and diameter of 167±47 nm and 8.24±2.28 nm, respectively, which gave an aspect ratio of about 20. The conductometric titration of aqueous CNCs suspension resulted in a carboxyl content of 0.24 mmol/g and the degree of oxidation was 0.04. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy clearly showed the presence of carboxyl group on the CNCs prepared by the APS oxidation. The change of pH of the aqueous CNC suspension from 4 to 7 converted the carboxyl group to sodium carboxylate group. These results showed that the APS oxidation was facile and CNCs had a one-step preparation method, and thus suggested an optimization of the oxidation condition in future.

• Korean Journal of Materials Research
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• v.12 no.9
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• pp.718-723
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• 2002

$Ti_{1-x}$ $Al_{ x}$N thin films as barrier layer for memory devices application were deposited by reactive magnetron sputtering. The crystallinity, micro-structure, oxidation resistance and oxidation mechanism of films were investigated as a function of Al content. Lattice parameter and grain size of thin films were decreased with increasing the Al content Oxidation of the film with higher Al content is slow and then, total oxide thickness is thinner than that of lower Al content film. Oxide layer formed on the surface is AlTiNO layer. Oxidation of $Ti_{1-x}$ /$Al_{x}$ N barrier layer is diffusion limited process and thickness of oxide layer with oxidation time increased with a parabolic law. The activation energy of oxygen diffusion, Ea and diffusion coefficient, D of $Ti_{0.74}$ /X$0.74_{0.26}$N film is 2.1eV and $10^{-16}$ ~$10^{-15}$ $\textrm{cm}^2$/s, respectively. $_Ti{1-x}$ /$Al_{x}$ XN barrier layer showed good oxidation resistance.

• Korean Journal of Plant Resources
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• v.26 no.2
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• pp.227-233
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• 2013

This study was carried out to effects of Allium victorials extract on lowering lipid, anti-oxidation and concentration of inflammatory mediators in rats fed high oxidized fat. Concentration of free fatty acid(FFA), triglyceride(TG), total cholesterol and LDL-cholesterol in plasma decreased in the Allium victorials extract groups and plasma HDL-cholesterol concentration revealed a tendency to increase in Allium victorials extract groups. Concentration of total cholesterol and TG in liver showed a tendency to decrease in Allium victorials extract groups. Concentration of thiobarbituric acid(TBARS) in plasma and liver showed a lower values in Allium victorials extract groups than that of control group. Activities of glutathione peroxidase(GSH-Px), superoxide dismutase(SOD) and catalase(CAT) in liver showed a tendency to increase in Allium victorials extract groups. Concentration of nitrogen oxide(NO), ceruloplasmin and ${\alpha}1$-acid glycoprotein in plasma showed a lower values in Allium victorials extract groups than that of control group. These results indicate that the Allium victorials extract have an functional material for lowering lipid, anti-oxidation and anti-inflammatory effect.

• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.49-55
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• 2010

The oil spill occurred frequently due to probably the increased consumption of oil as the energy source and the raw materials of various chemicals. For the treatment of oil contaminated groundwater, DAF(Dissolved Air Flotation) is being used but the removal efficiency is low. Therefore it is necessary to reduce the free phase oil, oil-in water type or water-in oil type emulsified oil, and soluble oil which are the main sources of contaminated groundwater. In this study, treatment of contaminated groundwater was performed using the Fenton oxidation process. The optimum conditions for the removal of THP(Total Petroleum Hydrocarbon) were 3 of pH, 25mM of $H_2O_2$ concentration and 25mM of $Fe^{2+}$ concentration. THP and COD(Chemical Oxygen Demand) concentrations decreased less than 1.5mg/L and 40.0mg/L in 7 minutes using DAF and Fenton oxidation process. However it is necessary to install the settling basin as the sludge concentration increased approximately 5 times.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.6
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• pp.83-89
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• 2000

A depot encircled with contact oxidation canal has been developed to improve water qualityr. The depot is aimed to settle suspended solid in the flow. The oxidation canal is to contact the pollutants and oxygen in the surface of gravel filter to purify the water. The deposit of the pollutant in the depot is released by the drainage culvert located at the bottom of it. Aeration nozzle is installed to supply enough oxygen to the gravel filter layers in the bottom of the detent the flow and improve oxidation efficiency. From the experiment it is founded that 91% of SS, 39% of TN, 63% of TP and 77% of COD were removed in the system. The treatment efficiency of total nitrogen is rather lower than any other components, however, it would be higher when some floating vegetation is added in the primary clarifier. The depot and oxidation canal system would be useful to purify the flows in the mouth of the reservoirs or at the outlet of the drainage canal.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.72-78
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• 1998

For investigation into gas permeation characteristics, the porous alumina membrane with asymmetrical structure, having upper layer with 10 nanometer under of pore diameter and lower layer with 36 nanometer of pore diameter, was prepared by anodic oxidation using DC power supply of constant current mode in an aqueous solution of sulfuric acid. The aluminium plate was pre-treated with thermal oxidation, chemical polishing and electrochemical polishing before anodic oxidation. Because the pore size depended upon the electrolyte, electrolyte concentration, temperature, current density, and so on, the the membranes were prepared by controling the current density, as a very low current density for upper layer of membrane and a high current density for lower layer of membrane. By control of current quantity, the thicknesses of upper layer of membranes were about $6{\;}{\mu}m$ and the total thicknesses of membranes were about $80-90{\;}{\mu}m$. We found that the mechanism of gas permeation depended on model of the Knudsen flow for the membrane prepared at each condition.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.141-147
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• 1993

A brief route for total synthesis of 6-deoxybisanhydrodaunomycinone(20) was described, namely the precursor of the daunomycinone, the aglycone of the anticancer antibiotic daunorubicin (1b). The prepared enone 4 was condensed with phthalide sulfone 7 to afford anthraquinone 10 after oxidation and methylation. The benzylic group of 10 was brominated, and subsequent oxidation with bis(tetrabutylammonium) dichromate followed by cyclization give hydroxyanthraquinone 16, which was displaced with thiophenol. Oxidation of 17 with m-CPBA in phosphate buffer solution afforded anthraquinonyl sulfone 18 which was condensed with methyl vinyl ketone (19) to furnish 20.

• Journal of Life Science
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• v.5 no.2
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• pp.70-75
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• 1995

The effect of lipoxygenase (LOX) on the oxidation and co-oxidation of lipid fraction was studied in the model system of rainbow trout. For the reaction in model system 1 g of lipid fraction and 50mL of enzyme extract(LOX, 140 unit in 50mL phosphate buffer solution at pH 7, 4)), which were obtained from rainbow trout, were homoginized in the presence of Tween 20 and kept at 23$\circ$C for 3 days. The activity of LOX was decreased to 43% of initial level during the reaction in the model system. The initial composition of rainbow trout lipid was showed to be consisted of trigliceride(TG;82%) and free fatty acid(FFA;0.1%), while this converted to 59% of TG and 20% of FIFA, respectively after reaction in model system. Change of fatty acid composition was also observed and the content of linoleic acid, one of the major fatte acids, was decreased to 13% from 54% in the content of total fatty acids after reaction. The carotenoids in rainbow trout were composed of 0.4% $\alpha$-carotene, 1.6% $\beta$ -carotene, 80% canthaxanthin, 7% lutein and 11% zeaxanthin, thus the canthaxanthin was the major component. This canthaxanthin was the most degraded carotenoid by lipoxygenase catalyzed co-oxidation during the reaction. On the other hand the tocopherol isomers found in the rainbow trout were $\alpha$ and $\beta$ -tocopherol, and $\alpha$-tocopherol had a higher degradation rate by the lipoxygenase catalyzed co-oxidation than of $\beta$-tocopherol in the reaction of model system.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.2
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• pp.119-126
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• 2002

The methanol partial oxidation using commercial $CuO/ZnO/Al_2O_3$ catalysts in a plug flow reactor was studied in the temperature range of $200{\sim}250^{\circ}C$ at atmospheric pressure, It was achieved the high activities by Cu-based catalysts and the selectivity of $CO_2$/$H_2$ was 100% when $O_2$ was fully convened. The reactivity changes and their hysteresis with increasing/decreasing temperatures were observed due to the chemical state differences between the oxidation and the reduction on the Cu surface, It was suggested as the two-step reaction: the complete oxidation and the following steam reforming for methanol, which was indicated by the distributions of final products vs. the residence time. In addition, the complete oxidation step was shown to be extremely fast and the total reaction rate can be controlled by the steam reforming reaction.

• Korean Journal of Community Nutrition
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• v.20 no.6
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• pp.468-478
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• 2015

Objectives: The objective of this study was to evaluate the thermic effects, the macronutrient oxidation rates and the satiety of medium-chain triglycerides (MCT). Methods: The thermic effects of two meals containing MCT or long-chain triglycerides (LCT) were compared in ten healthy men (mean age $24.4{\pm}2.9years$). Energy content of the meal was 30% of resting metabolic rate of each subject. Metabolic rate and macronutrient oxidation rate were measured before the meals and for 6 hours after the meals by indirect calorimetry. Satiety was estimated by using visual analogue scales (VAS) at 8 times (before the meal and for 6 hours after meal). Results: Total thermic effect of MCT meal (42.8 kcal, 8.0% of energy intake) was significantly higher than that (26.8 kcal, 5.1% of energy intake) of the LCT meal. Mean postprandial oxygen consumption was also significantly different between the two types of meals (MCT meal: $0.29{\pm}0.35L/min$, LCT meal: $0.28{\pm}0.27L/min$). There were no significant differences in total postprandial carbohydrate and fat oxidation rates between the two meals. However, from 30 to 120 minutes after consumption of meals, the fat oxidation rate of MCT meal was significantly higher than that of the LCT meal. Comparison of satiety values (hunger, fullness and appetite) between the two meals showed that MCT meal maintained satiety for a longer time than the LCT meal. Conclusions: This study showed the possibility that long-term substitution of MCT for LCT would produce weight loss if energy intake remained constant.