• Journal of the Korean Magnetic Resonance Society
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• v.23 no.3
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• pp.81-86
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• 2019

Overhauser dynamic nuclear polarization (O-DNP) has been an efficient method to boost the thermal nuclear polarization in liquids at room temperature. However, O-DNP for a benchtop NMR using a permanent magnet has remained unexplored yet. In this work, we report the development of an O-DNP system adopting a permanent magnet of 1.6 T. Q-band (~43 GHz) high-power amplifier produced 6 W microwave for saturation. Instead of resonator, we used an open-type antenna for the microwave irradiation. For several representative small molecules, we measured the concentration and frequency dependences of the enhancement factor. This work paves the way for the development of a benchtop DNP-NMR system overcoming its disadvantage of low quality signal when using a permanent magnet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.864-869
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• 2003

In order to expand the acceptability of irradiated foods by public, substantial basic data about the change of nutrient contents during irradiation are needed. The nutrient contents and digestibility of macronutrients such as carbohydrates, proteins and lipids in foods are known to be not significantly influenced by irradiation treatment. However, some of the vitamins among micronutrients are susceptible to irradiation to a large extent depending upon the food composition, food process and storage condition. This study was conducted to investigate change of thiamin in chicken breast, and vitamin C in strawberry and mandarine orange after irradiation. The effects of irradiation at frozen or refrigerated state and the effects of cooking such as heating or micron ave on thiamin contents in chicken breast were observed. Irradiation reduced the thiamin content, however, temperature condition during irradiation was much more important factor to the loss of thiamin contents. In strawberry, vitamin C content was significantly affected by original content or the variety rattler than treatments such as irradiation, heating or microwave. These results indicated that the losses of water-soluble vitamins, especially thiamin or vitamin C, are affected by food temperature during irradiation process and variety or composition of foods rallier than irradiation itself, within an acceptable range of irradiation.

• Journal of Industrial Technology
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• v.37 no.1
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• pp.21-26
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• 2017

This work experimentally determined the effect of combining of microwave irradiation and the Fenton process on decolorization of methylene blue ($C_{16}H_{18}N_3SCl$, MB). As [$H_2O_2$] increased from 2.65 to 4.41 mM, the decolorization of MB increased from 22.7 to 99.1%. As [$Fe^{2+}$] increased from 0.07 to 0.18 mM, the decolorization of MB increased from 24.0 to 98.5%. MB removal efficiencies were ${\geq}95%$ at $[H_2O_2]{\geq}3.5mM$ and $3.5{\leq}[H_2O_2]/[Fe^{2+}]{\leq}17.3$, but $[H_2O_2]/[Fe^{2+}]{\geq}20$ caused a decrease in MB removal. A two-stage kinetic model matched the experimental data well.

• Environmental Engineering Research
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• v.24 no.2
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• pp.191-201
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• 2019

Petroleum industry produces one of the popular hazardous waste known as Petroleum Sludge. The treatment and disposal of petroleum sludge has created a major challenge in recent years. This review provides insights into various approaches involved in the treatment, and disposal of petroleum sludge. Various methods used in the treatment and disposal of petroleum sludge such as incineration, stabilization/solidification, oxidation, and bio-degradation are explained fully and other techniques utilized in oil recovery from petroleum sludge such as solvent extraction, centrifugation, surfactant EOR, freeze/thaw, pyrolysis, microwave irradiation, electro-kinetic method, ultrasonic irradiation and froth flotation were discussed. The pros and cons of these methods were critically considered and a recommendation for economically useful alternatives to disposal of this unfriendly material was presented.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.356-356
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• 2006

The use of renewable feedstock is an important issue to reduce the fossil fuel consumption. In this contribution, we report the cationic ring-opening polymerization of a 2-oxazoline monomer with soybean fatty acid side chains (SoyOx) under microwave irradiation. Kinetic experiments were performed to investigate the livingness of the polymerization in both acetonitrile and in the absence of solvent. In addition, both block and statistical copolymers were prepared using the SoyOx monomer. The synthesized (co)polymers were crosslinked under UV-irradiation resulting in insoluble polymeric materials and core-crosslinked micelles.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.541-545
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• 2011

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1825-1826
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• 2010

• Toxicological Research
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• v.5 no.2
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• pp.89-96
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• 1989

Rapid and complete epidermal-dermal separation procedure were determined in neonatal rat skin by light microscopic observation and by compairing enzyme activities in the separated epidermis. Microscopic appearance demonstrated the at four different separation procedures used in the study resulted in good separation of epidermis from dermis` heating method (i.e., immersion in 55C water for 30 sec, followed by immersion in 0-4C water) and microwave irradiation for 10 sec were saving time.

• Preventive Nutrition and Food Science
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• v.9 no.1
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• pp.53-57
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• 2004

The purpose of this study was to investigate the effects of green tea catechin on mixed function oxidase system (MFO), lipofuscin contents, carbonyl value, oxidative damage and the antioxidative defense system in lung of microwave exposed rats. Experimental groups were divided to normal group and microwave exposed group. The microwave exposed groups were subdivided into three groups: catechin free diet (MW-0C) group, 0.25% catechin (MW-0.25C) group and 0.5 ％ catechin (MW-0.5C) group according to the levels of dietary catechin supplementation. The rats were irradiated with microwave at frequency of 2.45 GHz for 15 min. Experimental animals were sacrificed at 6th day after microwave irradiation. The contents of cytochrome P$_{450}$ contents in MW-0C group was increased to 95% , compared with normal group. MW-0.25C and MW-0.5C groups were reduced to 16% and 31%, respectively, compared with MW-0C group. The activity of NADPH-cytochrome P$_{450}$ reductase in MW-0C group was increased to 44%, compared with normal group. MW-0.25C and MW-0.5C groups were reduced to 12% and 17％, respectively, compared with MW-0C group. The activity of superoxide dismutase (SOD) in MW-0C group was decreased to 21 ％, compared with normal group. MW-0.25C and MW-0.5C group were significantly (p < 0.05) increased, compared with MW-0C group. The activity of glutathione peroxidase (GSHpx) in MW-0C group was significantly decreased, compared with normal group. MW-0.25C and MW-0.5C groups were recovered to the level of normal group. The thiobarbituric acid reactive substances (TBARS) content in MW-0C group was increased to 34 ％, compared with normal group. Catechin supplementation groups were maintained the level of normal group. The levels of caybonyl value in MW-0C group was increased to 21 ％, compared with normal group. MW-0.25C and MW-0.5C groups were reduced to 14% and 12%, respectively, compared with MW-0C group. The lipofuscin contents in MW-0C group were increased to 23.4 ％, compared with normal group. That of MW-0.5C group was significantly reduced, compared with MW-0C group. In conclusion, MFO system was activated and the formation of oxidized protein, lipofuscin was increased and antioxidative defense system was weakened of lung tissue in microwave exposed rats, thus oxidative damage was increased. But it was rapidly recovered to normal level by green tea catechin supplementation.n.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.3
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• pp.311-319
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• 2013

The purpose of the present study is to investigate the effects of green tea catechin on microsomal phospholipase $A_2(PLA_2)$ activity and the arachidonic acid (AA) cascade in hearts of microwave exposed rats. Sprague-Dawley male rats weighing $100{\pm}10$ g were randomly assigned to one normal group and three microwave exposed groups. The microwave exposed groups were subdivided into three groups: catechin free diet (MW) group, 0.25% catechin (MW-0.25C group and 0.5% catechin (MW-0.5C) group according to the levels of dietary catechin supplementation. Rats were sacrificed $6^{th}$ day after microwave irradiations (2.45 GHz, 15 min). The heart microsome $PLA_2$ activity in the MW group was 130% greater than that of normal groups, whereas there was no significant difference between normal group and MW-0.25C, MW-0.5C group. The per- centage phosphatidyl ethanolamine (PE) hydrolyzed in the heart microsome in the MW was increased 54% by microwave irra- diation, whereas there was no significant difference between normal group and MW-0.5C group. The percentage phosphatidyl choline (PC) hydrolyzed in the heart microsome in the MW group was increased by 104% and by microwave irradiation, whereas there was no significant difference between normal group and MW-0.5C group. The formation of thromboxane $A_2(TXA_2)$ in the heart microsome was 70% greater in the MW group than in the normal group. However, the MW-0.25C and MW-0.5C group maintained the normal level. The formation of prostacyclin ($PGI_2$) in the heart microsome was 21% lower in the MW group than in the normal group, while that of MW-0.25C and MW-0.5C group were maintained in the normal group. The heart microsomal thiobarbituric acid reactive substances (TBARS) concentrations, as an index of lipid peroxide, were 71% greater in the MW group, as compared with normal group. However, the MW-0.25C and MW-0.5C group were 4.6% and 9.2% lower, respectively, than that of MW group. In conclusion, heart function appeared to be improved by green tea catechin supplementation due to its antithrombus action, which in return controls the AA cascade system.