• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.3
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• pp.214-219
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• 1991

The damaging effect of peroxidized lipid on amino acid was studied in rice bran by determining the free amino acid content in abiological system. The content of free amino acid in the rice bran stored in the controlled atomsphere of $35^{\circ}C$ with relative humidity of 65% for 180 days, increased during the first 60 days of storage, and then decreased as the lipid peroxidation proceeded. The content of free amino acid in the sample exposed to the air of $25-30^{\circ}C$ with relative humidity of 70-90% for 100 days decreased rapidly in the beginning period of the storage. The lipid oxidation developed much faster in the rice bran exposed to the air than in the rice bran stored in the controlled atmosphere. The correlation coefficients between the total content of free amino acid and degree of peroxidation for the samples of both conditions were above -0.8, which is significant(p<0.05). The changes in the concentration of serine, glutamic acid, proline, methionine, lysine, histidine, and arginine were significantly correlated with the degree of lipid oxidation(p<0.05) for the samples stored in the controlled atmosphere and the open air. It was observed that peroxidized lipid has damaging effects on protein in the bilogical system of rice bran.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.169-173
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• 2005

Ni oxide thin films were formed through annealing treatment in the atmosphere after Ni thin films deposited by a r.f. magnetron sputtering method and then electric and material properties were analyzed for application to thermal sensors. Resistivity of Ni thin films decreased after annealing treatment at 30$0^{\circ}C$ and 40$0^{\circ}C$ for five hours due to crystallization of Ni thin films but the value increased over 45$0^{\circ}C$ because of Ni thin film's oxidation. Resistivity values of Ni thin films were in the range of 10.5 $\mu$Ωcm/$^{\circ}C$ to 2.84${\times}$10$^4$$\mu$Ωcm/$^{\circ}C$ according to the degree of Ni oxidation. Also temperature coefficient of resistance(TCR) values of Ni oxide thin films depended on the degree of Ni oxidation such as 2,188 ppm/$^{\circ}C$ to 5,630 ppm/$^{\circ}C$ in the temperature range of 0 $^{\circ}C$∼150 $^{\circ}C$. The results demonstrate that Ni oxide thin films of annealing treatment at 40$0^{\circ}C$ for 5hours could be more advantageous than pure Ni thin films and Pt thin films from a point of output properties and TCR, applied to thermal sensors.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.1011-1017
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• 2010

Sunflower oil (SO), canola oil (CO) and frying oil (FO) were used as edible oils in this study. According to the frying number, the extracted oils from French fried potatoes were used as experimental samples. To investigate the relationship between the change of fatty acid composition and the stability of the lipid oxidation during frying, the changes of fatty acid composition and the degree of the lipid oxidation of samples were examined. Acid values and peroxide values were evaluated as the degree of lipid oxidation. The acid values of CO and FO were increased with the frying times. The increased acid values of CO and FO were 0.20 and 0.17 on the basis of initial value at 30 times, respectively, but the acid value of SO was lower than those of CO and FO. The peroxide values of the samples were not increased uniformly with the frying number. As the number of frying times was increased, the fatty acid composition of SO and FO were changed. Namely, the oleic acid composition was decreased, whereas the linoleic acid composition was increased with the number of frying times. The benzo(a)pyrene contents of the extracted oils from French fried potatoes did not change regularly as the frying times was increased.

• Advances in nano research
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• v.13 no.6
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• pp.513-525
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• 2022

In this study, it was aimed to evaluate direct oxidation of aqueous solution containing cefalexin antibiotic with new generation Sn/Sb/Ni: 500/8/1 anode. The fact that there is no such a study on treatment of cefalexin with these new anode made this study unique. According to the operating parameters evaluation COD graphs showed clearer results compared to TOC and CLX and thus, it was it was chosen as major parameter. Furthermore, pseudo-first degree kd values were calculated from CLX results to show more accurate and specific results. Experimental results showed that after 60 min of electrochemical oxidation, complete removal of COD and TOC was accomplished with 750 mg L^-1 KCl, at pH 7, 50 mA cm^-2 current density and 1 cm anode-cathode distance. Also, the stability of the Sn/Sb/Ni anode was evaluated by taking SEM and AFM images and XRD analysis before and after of electrochemical oxidation processes. According to the results, it was not occurred too much change on the anode surface even after 300 h of electrolysis. Thus, it was thought that the anode material was not corroded to a large extent. Furthermore, the removal efficiencies were very high for almost all the time and conditions. According to the results of the study, electrochemical oxidation with new generation Sn/Sb/Ni anodes for the removal of cefalexin antibiotic was found very successful and applicable due to require less reaction time complete mineralization and doesn't require pH adjustment step compared to other studies in literature. In future studies, different antibiotic types should be studied with this anode and maybe with real wastewaters to test applicability of the process in treatment of pharmaceutical wastewaters containing antibiotics, in a better way.

• Corrosion Science and Technology
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• v.20 no.3
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• pp.158-168
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• 2021

Austenitic 316 stainless steel was irradiated with protons accelerated by an energy of 2 MeV at 360 ℃, the various defects induced by this proton irradiation were characterized with microscopic equipment. In our observations irradiation defects such as dislocations and micro-voids were clearly revealed. The typical irradiation defects observed differed according to depth, indicating the evolution of irradiation defects follows the characteristics of radiation damage profiles that depend on depth. Surface oxidation tests were conducted under the simulated primary water conditions of a pressurized water reactor (PWR) to understand the role irradiation defects play in surface oxidation behavior and also to investigate the resultant irradiation assisted stress corrosion cracking (IASCC) susceptibility that occurs after exposure to PWR primary water. We found that Cr and Fe became depleted while Ni was enriched at the grain boundary beneath the surface oxidation layer both in the non-irradiated and proton-irradiated specimens. However, the degree of Cr/Fe depletion and Ni enrichment was much higher in the proton-irradiated sample than in the non-irradiated one owing to radiation-induced segregation and the irradiation defects. The microstructural and microchemical changes induced by proton irradiation all appear to significantly increase the susceptibility of austenitic 316 stainless steel to IASCC.

• Journal of the Korean Society of Industry Convergence
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• v.15 no.3
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• pp.71-77
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• 2012

This study gives the optimal reaction conditions, reaction mechanisms, reaction rates leaded from the oxidation of phenol by electron beam accelerator and ozone used for recent water treatment. It gives the new possibility of water treatment process to effectively manage industrial sewage containing toxic organic compounds and biological refractory materials. The high decomposition of phenol was observed at the low dose rate, but at this low dose rate, the reaction time was lengthened. So we must find out the optimal dose rate to promote high oxidation of reactants. The reason why the TOC value of aqueous solution wasn't decreased at the low dose was that there were a lot of low molecular organic acids as an intermediates such as formic acid or glyoxalic acid. In order to use both electron beam accelerator and biological treatment for high concentration refractory organic compounds, biological treatment is needed when low molecular organic compounds exist abundantly in sewage. In this experiment, the condition of making a lot of organic acids is from 5 kGy into 20 kGy dose. Decomposition rate of phenol by electron beam accelerator was first order reaction up to 300ppm phenol solution on the basic of TOC value and also showed first order reaction by using both air and ozone as an oxidants.

• Advances in environmental research
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• v.5 no.4
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• pp.251-262
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• 2016

The biodegradability and decomposition efficiencies increase with the pre-treatment of sludge in a digestion process. In this study, the feasibility of ultrasound coupled with potassium permanganate oxidation as a disintegration method and digestibility of aerobic reactor fed with disintegrated sludge with ultrasound coupled potassium permanganate were investigated. The first stage of the study focused on determining the optimum condition for ultrasonic pre-treatment for achieving better destruction efficiency of sludge. The second part of the study, the aerobic digestibility of sludge disintegrated with ultrasound and potassium permanganate oxidation alone and combined were examined comparatively. The results showed that when 20 min of ultrasonic pre-treatment applied, the specific energy output was 49384 kJ/kgTS with disintegration degree of 58.84%. During the operation of aerobic digester, VS/TS ratios of digesters fed with disintegrated sludge decreased indicating that disintegration methods could obviously enhance aerobic digestion performance. The highest reduction in volatile solids was 75% in the digester fed with ultrasound+potassium permanganate disintegrated sludge at the end of the operation compared to digester fed with raw sludge. Total Nitrogen (TN) and Total Phosphorus (TP) levels in sludge supernatant increased with this combined method significantly. Besides, it promoted the production of ${\bullet}OH$, thus enhancing the release of Carbon (C), Nitrogen (N) and Phosphorus (P) from the sludge. Disintegration with all methods used in this study could not improve Capillary Suction Time (CST) reduction in disintegrated digesters during the operation. The results demonstrated that the combined ultrasound treatment and potassium permanganate oxidation method improves the biodegradability compared to control reactor or their single application.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.3
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• pp.315-324
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• 1997

Physicochemical properties of potato starches oxidized with sodium hypochlorite containing 1.5, 3.0, 4.5, and 6.0% active Cl/g starch at pH 7.0 were examined. Carboxyl group contents of oxidized potato starches were proportional to active chlorine concentration in use and water binding capacity, alkali number, and solubility increased with increasing the degree of oxidation. Blue value and iodine binding property indicated the change of amylose structure by the oxidation. Gelatinization trends obtained from transmittance and DSC thermograms showed that gelatinization temperature was lower as starch was oxidized higher. X-ray diffraction patterns and scanning electron micrographs implied oxidation might occur on the surface amorphous regions of starch granule.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.3
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• pp.270-272
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• 2005

The behavior of surface oxidation on cobalt silicide layer was investigated under rapid thermal oxidation (RTO) conditions. The cobalt silicide layer was prepared on p-type silicon substrates. We used Ti thin film as a capping layer in order to measure the degree of oxidation of the layer. Oxide grew faster on the cobalt silicide prepared with the Ti capping layer to reach ca $500{\AA}$ at $700^{\circ}C$ in thickness. The oxide film kept growing under $550^{\circ}C\~700^{\circ}C$ of the RTO condition, resulting in a saturated state above $500{\AA}$.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.33-36
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• 2003

AC and DC conductivity of the MWNT(Multi walled nanotubes)/polyurethane composites were investigated with respect to the various oxidative conditions, where these means acid concentration, treatment temperature, and treatment time. We suppose that the conditions of oxidation of the MWNTS have a certain influence on the degree of functionalization, damages, and dispersion of the MWNT themselves. Futhermore, the electrical properties of the resulting composites strongly depend on the oxidative conditions of MWNTS. The conductivity of the composites produced by using the optimal condition was measured as a function of frequency with volume content of MWNTS. These experimental results were analyzed using percolation theory Electromagnetic interference shielding effectiveness (SE) of the mixtures of polyurethane (PU), optimized MWNTs, and silver (Ag) is measured in the frequency range from 10 MHz to 6 ㎓ by using ASTM D4935-89. The measured SEs of the mixtures could be controlled from about 55 dB to 85 dB with the compositions of Ag/MWNT and compounding methods(C1, C2).