• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.171-177
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• 2011

This study was carried out to search for natural anti-oxidants and anti-inflammatory compounds from 5 medicinal plants (Carthamus tinctorius seed, Cyperus rotundus, Schizonepeta tenuifolia, Polygonatum odoratum var. pluriflorum, and Paeonia lactiflora). These plants were extracted with 70% ethanol. In order to measure total antioxidant activity of flavonoids, polyphenol content was measured. Radical scavenging activities of extracts were examined using a-a-Diphenyl-${\beta}$-picrylhydrazyl ($DPPH{\cdot}$), 2,2-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid ($ABTS{\cdot}$), ferric reducing antioxidant power (FRAP) and superoxide anion radical assays. C. tinctorius seed extracts showed the highest polyphenol and flavonoid contents as well as strong $DPPH{\cdot}$, $ABTS{\cdot}$, FRAP, and superoxide anion radical scavenging activity. Also, C. tinctorius seed extracts showed the highest nitric oxide (NO) production inhibitory effect. Theses results indicate that the C. tinctorius seed extracts can be used as a functional material due to their effective anti-oxidative and antiinflammatory activities.

• Nuclear Engineering and Technology
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• v.40 no.6
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• pp.497-504
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• 2008

In a study of the optimum operational condition for a melting decontamination, the effects of the basicity, slag type and slag composition on the distribution of depleted uranium were investigated for radioactively contaminated metallic wastes of iron-based metals such as stainless steel (SUS 304L) in a direct current graphite arc furnace. Most of the depleted uranium was easily moved into the slag from the radioactive metal waste. The partitioning ratio of the depleted uranium was influenced by the amount of added slag former and the slag basicity. The composition of the slag former used to capture contaminants such as depleted uranium during the melt decontamination process generally consists of silica ($SiO_2$), calcium oxide (CaO) and aluminum oxide ($Al_2O_3$). Furthermore, calcium fluoride ($CaF_2$), magnesium oxide (MgO), and ferric oxide ($Fe_2O_3$) were added to increase the slag fluidity and oxidative potential. The partitioning ratio of the depleted uranium was increased as the amount of slag former was increased. Up to 97% of the depleted uranium was captured between the ingot phase and the slag phase. The partitioning ratio of the uranium was considerably dependent on the basicity and composition of the slag. The optimum condition for the removal of the depleted uranium was a basicity level of about 1.5. The partitioning ratio of uranium was high, exceeding $5.5{\times}10^3$. The slag formers containing calcium fluoride ($CaF_2$) and a high amount of silica proved to be more effective for a melt decontamination of stainless steel wastes contaminated with depleted uranium.

• Resources Recycling
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• v.13 no.2
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• pp.9-15
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• 2004

A large tons of spent iron oxide catalyst come from the Styrene Monomer(SM) production company. It is caused to pollute the land and underground water due to the high alkali contents in the catalyst by burying them in the landfill. In order to recycle the spent catalyst, a basic study on the recovery of chromium ion from metal plating wastewater with the spent catalyst was carried out. The iron oxide catalyst adsorbed physically $Cr^{+6}$ in the lower pH 3.0, that is the isoelectric point of the spent catalyst. It was found that the iron oxide catalyst reduced the $Cr^{+6}$ into Cr+3 by the oxidation of ferrous ion into ferric ion on the surface of catalyst, and precipitated as $Cr(OH)_3$ in the higher than pH 3.0. The $Cr^{+6}$ was recovered 2.0∼2.3g/L catalyst in the range of pH 0.5∼2.0, but it was recovered 1.5 g/L catalyst at pH 3.0 of wastewater. The recovery of Cr was increased as the higher concentration in the continuous process, but the flowrates were nearly affected on the Cr recovery.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.17-21
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• 2017

Vanadium slags is a kind of vanadiferous solid waste from steelmaking process. It not only occupies land, pollutes environment, but also leads to waste of resources. Based on the difference of magnetic susceptibility of different particles caused by their chemical and physical properties from vanadium slag, a new technology, superconducting high gradient magnetic separation was investigated for separation and extraction of valuable substances from vanadium slag. The magnetic concentrate was obtained under optimal parameters, i.e., a particle size -200 mesh, a magnetic flux density of 0.8 T, a slurry concentration of 5 g/L, an amount of steel wools of 25 g and a slurry flow velocity of 2 L/min. The content of $Fe_2O_3$ in concentrate could be increased from 39.6% to 55.0% and $V_2O_5$ from 2.5% to 4.0%, respectively. The recovery rate is up to 42.9%, and the vanadium slag has been effectively reused.

• Advances in nano research
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• v.9 no.1
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• pp.59-67
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• 2020

Filter cake formation during rotary drilling operation is an unavoidable scenario, hence there is need for constant improvement in the approaches used in monitoring the cake thickness growth in order to prevent drill-string sticking. This study proposes an improved model that predicts the growth of mud cake thickness overtime with the consideration of the addition of nanoparticles in the formulated drilling fluid system. Ferric oxide, titanium dioxide and copper oxide nanoparticles were used in varying amounts (2 g, 4 g and 6 g), and filtration data were obtained from the HPHT filtration test. The filter cakes formed were further analyzed with scanning electron microscope to obtain the morphological characteristics. The data obtained was used to validate the new filtrate loss model. This model specifically presents the concept of time variation in filter cake formation as against the previous works of constant and definite time. Regression coefficient which is a statistical measure was used to validate the new model and the predicted results were compared with the API model. The new model showed R² values of 99.9%, and the predictions from the proposed filtration model can be said to be more closely related to the experimental data than that predicted from the API model from the SSE and RMSE results.

• Food Science and Preservation
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• v.24 no.1
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• pp.116-124
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• 2017

In this study, we compared the antioxidant and immuno-modulatory effects of water (HR, HL, HS), 70% ethanol (ER, EL, ES), and 70% methanol (MR, ML, MS) extracts of different parts (root, leaf, and seed) from Glehnia Radix. Yields were 17.40-30.17% for water extract, 11.47-28.67% for 70% ethanol extract, and 10.73-30.57% for 70% methanol extract, respectively. The total polyphenol and flavonoid contents of EL were 10.79 g/100 g and 2.01 g/100 g, respectively. The DPPH and ABTS radical scavenging activities of EL at $1,000{\mu}g/mL$ were 84.70% and 57.64%, respectively. The superoxide radical scavenging and ferric-reducing antioxidant power of EL at $1,000{\mu}g/mL$ were 84.05% and $975.28{\mu}M$, respectively. Moreover, 70% ethanol and 70% methanol extracts of root from Glehnia Radix significantly inhibited production of NO in LPS-stimulated macrophage RAW 264.7 cells without cytotoxicity. These results suggest that 70% ethanol and 70% methanol extracts of Glehnia Radix leaf may be a useful functional food material in the food industry.

• Coupled systems mechanics
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• v.6 no.4
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• pp.465-485
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• 2017

In this paper, free vibration and static response of magneto-electro-elastic (MEE) beams has been investigated. To this end, a 3D finite element formulation has been derived by minimization the total potential energy and linear constitutive equation. The coupling between elastic, electric and magnetic fields can have a significant influence on the stiffness and in turn on the static behaviour of MEE beam. Further, different Barium Titanate ($BaTiO_3$) and Cobalt Ferric oxide ($CoFe_2O_4$) volume fractions results in indifferent coupled response. Therefore, through the numerical examples the influence of volume fractions and boundary conditions on the natural frequencies of MEE beam is illustrated. The study is extended to evaluate the static response of MEE beam under various forms of mechanical loading. It is seen from the numerical evaluation that the volume fractions, loading and boundary conditions have a significant effect on the structural behaviour of MEE structures. The observations made here may serve as benchmark solutions in the optimum design of MEE structures.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.447-458
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• 2024

In this study, the antioxidizing effect of 2,3-dicaffeoyl-epi-quinic acid (DEQA) was investigated. The antioxidant activity was evaluated by measuring the scavenging effect on DPPH radical and peroxynitrite and the reducing power on ferric ion. DEQA showed a scavenging effect and reducing power comparable to vitamin C used as a positive control. Also, DEQA effectively inhibited production of intracellular reactive oxygen species (ROS) in HT-1080 cells, showing the scavenging ratio of 43.8% even at 10 µM concentration of DEQA after 2 hours in HT-1080 treated with H₂O₂. In addition to this, DEQA inhibited the production of nitric oxide (NO) very effectively in Raw 264.7 cells. The above results suggest that DEQA has the potential to be developed as a natural antioxidant.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.125-130
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• 2010

In the present work, we have investigated the adsorption efficiency of carbon/iron oxide nanocomposite towards removal of hazardous brilliant green (BG) from aqueous solutions. Carbon/iron oxide nanocomposite was prepared by chemical precipitation and thermal treatment of carbon with ferric nitrate at $750^{\circ}C$. The resulting material was thoroughly characterized by TEM, XRD and TGA. The adsorption studies of BG onto nanocomposite were performed using kinetic and thermodynamic parameters. The adsorption kinetics shows that pseudo-second-order rate equation was fitted better than pseudo-first-order rate equation. The experimental data were analyzed by the Langmuir and Freundlich adsorption isotherms. Equilibrium data was fitted well to the Langmuir model with maximum monolayer adsorption capacity of 64.1 mg/g. The thermodynamic parameters were also deduced for the adsorption of BG onto nanocomposite and the adsorption was found to be spontaneous and endothermic.

• Carbon letters
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• v.15 no.3
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• pp.171-179
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• 2014

An attempt was made to investigate the effect of the preparation temperature on the electrocapacitive performance of polypyrrole (PPY)/graphene oxide (GO) nanocomposites (PNCs). For this purpose, a series of PNCs were prepared at various temperatures by the cetyltrimethylammonium bromide-assisted dilute-solution polymerization of pyrrole in presence of GO (wt%) ranging from 1.0 to 4.0 with ferric chloride as an oxidant. The formation of the PNCs was ascertained through Fourier-transform infrared spectrometry, X-ray diffraction spectra, scanning electron microscopy and simultaneous thermogravimetric-differential scanning calorimetry. The electrocapacitive performance of the electrodes derived from sulphonated polysulphone-bound PNCs was evaluated through cyclic voltammetry with reference to Ag/AgCl at a scan rate (V/s) ranging from 0.2 and 0.001 in potassium hydroxide (1.0 M). The incorporation of GO into the PPY matrix at a reduced temperature has a pronounced effect on the electrocapacitive performance of PNCs. Under identical scan rates (0.001 V/s), PNCs prepared at $10{\pm}1^{\circ}C$ render improved specific conductivity (526.33 F/g) and power density (731.19 W/Kg) values compared to those prepared at $30{\pm}1^{\circ}C$ (217.69 F/g, 279.43 W/Kg). PNCs prepared at $10{\pm}1^{\circ}C$ rendered a capacitive retention rate of ~96% during the first 500 cycles. This indicates the excellent cyclic stability of the PNCs prepared at reduced temperatures for supercapacitor applications.