• Journal of Powder Materials
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• v.28 no.6
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• pp.470-477
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• 2021

Energy storage systems should address issues such as power fluctuations and rapid charge-discharge; to meet this requirement, CoFe₂O₄ (CFO) spinel nanoparticles with a suitable electrical conductivity and various redox states are synthesized and used as electrode materials for supercapacitors. In particular, CFO electrodes combined with carbon nanofibers (CNFs) can provide long-term cycling stability by fabricating binder-free three-dimensional electrodes. In this study, CFO-decorated CNFs are prepared by electrospinning and a low-cost hydrothermal method. The effects of heat treatment, such as the activation of CNFs (ACNFs) and calcination of CFO-decorated CNFs (C-CFO/ACNFs), are investigated. The C-CFO/ACNF electrode exhibits a high specific capacitance of 142.9 F/g at a scan rate of 5 mV/s and superior rate capability of 77.6% capacitance retention at a high scan rate of 500 mV/s. This electrode also achieves the lowest charge transfer resistance of 0.0063 Ω and excellent cycling stability (93.5% retention after 5,000 cycles) because of the improved ion conductivity by pathway formation and structural stability. The results of our work are expected to open a new route for manufacturing hybrid capacitor electrodes containing the C-CFO/ACNF electrode that can be easily prepared with a low-cost and simple process with enhanced electrochemical performance.

• The Korea Journal of Herbology
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• v.27 no.6
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• pp.1-6
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• 2012

Objectives : ROS are involved in a wide spectrum of diseases including chronic inflammation and cancer. S.chinensis Baill, a perennial herb commonly called Chinese lizard's tail or Sam-baek-cho in Korea, is used for the treatment of edema and inflammatory diseases in the Oriental folk medicine. In this study, we investigated the antioxidant activities and anti-inflammatory effects of the two extracts, water(WE) and ethyl acetate(EAE) from S.chinensis Baill. Methods : Anti-oxidant activity was evaluated using Fe2+ chelating and hydroxyl radical scavenging assay. DNA cleavage assay, and western blot and immunostaining for phospho-p65 were performed to evaluate anti-oxidative effect. Anti-inflammatory effect was performed using NO generation assay and western blot in LPS-stimulated RAW264.7 cell. Results : In Fe2+ chelating activity and hydroxyl radical scavenging activity, WE showed more strong scavenging activity for hydroxyl radical than EAE. WE scavenged hydroxyl radical by 12% at 3.2 ${\mu}g/ml$, 21% at 16 ${\mu}g/ml$, 32% at 80 ${\mu}g/ml$, 66% at 400 ${\mu}g/ml$ and 82% at 2000 ${\mu}g/ml$, respectively. In addition, WE showed more strong chelating activity than EAE. WE chelated Fe2+ ion by 1.1% at 3.2 ${\mu}g/ml$, 8.2% at 16 ${\mu}g/ml$, 26.3% at 80 ${\mu}g/ml$, 72% at 400 ${\mu}g/ml$ and 89% at 2000 ${\mu}g/ml$, respectively. Also, WE inhibited oxidative damage via its anti-oxidant activity. In anti-inflammatory effect, EAE inhibited NO production and iNOS expression. In addition EAE suppressed the NF-${\kappa}B$ and MAPK signaling pathway in LPS-stimulated RAW 264.7 cells. Conclusions : Together, these data indicate that S. chinensis Baill, shows anti-oxidant activity and anti-inflammatory effect.

• Journal of Bio-Environment Control
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• v.19 no.2
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• pp.70-76
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• 2010

To investigate the ground water quality status for paprika hydroponics for export, its pH, EC (electrical conductivity) and inorganic ion concentrations were analyzed in Gangwan-do (27 samples), Gyeonsangnam-do (77 samples) and Jeollanam-do (54 samples) from November 2008 to September 2009. The average values of several components in ground water were as follows; 7.20 (6.57~7.54) in pH, 0.31 (0.05~0.49) $dS{\cdot}m^{-1}$ in EC, 97.81 (35.37~161.11) in $HCO_3$, 5.68 (0.45~15.48) in T-N, 0.67 (0.15~0.70) in P, 2.53 (0.59~6.70) in K, 35.68 (4.15~80.70) in Ca, 7.35 (1.46~14.87) in Mg, 17.89 (3.31~34.82) in Na, 0.01 (0~0.05) in Fe, 0.09 (0~0.51) in Mn, 0.06 (0~0.07) in Zn, and 0.03 (0~0.10) $mg{\cdot}L^{-1}$ in Cu, respectively. The values of pH, EC, $HCO_3$, Ca, Mg and Na in ground water were different depending on areas and farms. Frequency rates were 92.6% of pH 5.0~8.0, 89.3% of EC < 0.5 $dS{\cdot}m^{-1}$, 69.5% of $HCO_3$ < 100, 97.5% of Na < 30, 88.5% of Ca < 40, 97.5% of Mg < 20, 90.1% of Fe < 0.05, 99.6% of Mn < 0.6, and 98.3% of Zn < 0.5 $mg{\cdot}L^{-1}$, respectively, which can be used for nutrient fertilizers in hydroponics. The percentage of suitable water quality was 46.3% as 70 sites among the all analyzed ions. The pH value showed high significance of correlations with EC, Mg, $HCO_3$, Na, and Fe. Also the EC value showed high positive significance with T-N, K, Ca, Mg, $HCO_3$, Na and Mn.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.299-314
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• 2008

The NE-trending Honam shear zone is a broad, dextral strike-slip fault zone between the southern margin of the Okcheon Belt and the Precambrian Yeongnam Massif in South Korea and is parallel to the trend of Sinian deformation that is conspicuous in Far East Asia. In this paper, we report geochemical and isotopic(Sr and Nd) data of mylonitic quartz-muscovite Precambrian gneisses and surrounding foliated hornblende-biotite granitoids near the Myeongho area in the Yecheon Shear Zone, a representative segment of the Honam Shear Zone. Foliated hornblende-biotite granitoids commonly plot in the granodiorite field($SiO_2=61.9-67.1\;wt%$ and $Na_2O+K_2O=5.21-6.99\;wt%$) on $SiO_2$ vs. $Na_2O+K_2O$ discrimination diagram, whereas quartz-muscovite Precambrian orthogneisses plot in the granite field. The foliated hornblende-biotite granitoids are mostly calcic and calc-alkalic and are dominantly magnesian in a modified alkali-lime index(MALI) and Fe# [$=FeO_{total}(FeO_{total}+MgO)$] versus $SiO_2$ diagrams, which correspond with geochemical characteristics of Cordilleran Mesozoic batholiths. The foliated hornblende-biotite granitoids have molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 0.89 to 1.10 and are metaluminous to weakly peraluminous, indicating I type. In contrast, Paleoproterozoic orthogneisses have peraluminous compositions, with molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 1.11 to 1.22. On trace element spider diagrams normalized to the primitive mantle, the large ion lithophile element(LILE) enrichments(Rb, Ba, Th and U) and negative Ta-Nb-P-Ti anomalies of foliated hornblende-biotite granitoids and mylonitized quartz-muscovite gneisses in the Yecheon Shear Zone are features common to subduction-related granitoids and are also found in granitoids from a crustal source derived from the arc crust of active continental margin. ${\varepsilon}_{Nd}(T)$ and initial Sr-ratio ratios of foliated hornblende-biotite granitoids with suggest the involvement of upper crust-derived melts in granitoid petrogenesis. Foliated hornblende-biotite granitoids in the study area, together with the Yeongju Batholith, show not changing contents of specific elements(Ti, P, Zr, V and Y) from shear zone to the area near the shear zone. These results suggest that no volume changes and geochemical alterations in fluid-rich foliated hornblende-biotite granitoids may occur during deformation, which mass transfer by fluid flow into the shear zone is equal to the mass transfer out of the shear zone.

• Journal of Life Science
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• v.27 no.4
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• pp.390-397
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• 2017

Iron (Fe) is an important micronutrient for the health and growth of plants. Iron is usually provided by fertilizers, and iron-chelate fertilizers are well absorbed by plants. This study presents the plant growth-promoting effects of a new functional iron fertilizer, Fe-chelating crab shell powder (FCSP), which is generated from the chelation of Fe ions with crab shell powder. Iron chelate was derived from spent pickling liquor, which is rich in reductive iron, iron(II) oxide. To analyze the effects of FCSP on plant growth, we treated lettuce with several concentrations of FCSP in both lab- and field-scale experiments. In the lab-scale test, the treatment of 50 ppm of FCSP highly promoted growth and resulted in increases in the size, weight, number and chlorophylls content of leaves of plants compared to the treatment of crab shell powder. Fifty ppm of FCSP also increased the size and weight of leaves up to 2 times compared to the application of chemical fertilizer and/or compost in field conditions. In addition, the FCSP treatment resulted in the highest ion uptake of Fe in lettuce leaves. Moreover, FCSP led to increases in the amounts of Fe, Ca, available phosphorus and organic matter in treated soil, indicating that soil quality was improved. Taken together, our results demonstrate that FCSP promotes lettuce growth via enhancement of Fe availability and improves soil quality. Therefore, FCSP can be utilized as a new functional iron fertilizer.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.3
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• pp.179-186
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• 2003

This pot experiment was conducted to find out the effects of boron application( $B_{0}$ ) ; control, B$_1$; 0.2, $B_2$; 2.0, $B_3$; 6.0, $B_4$; 15.0 boron me/pot) on the forage performance of pure and mixed cultures of orchardgrass and white clover. The fourth part was concerned with the changes in the contents of B, Fe, Mn, Cu, and Zn in forages. The results obtained are summarized as follows: 1. The boron(B) contents of both forages and their differences among the B treatments generally decreased according to the cutting order. The B contents of white clover were somewhat lower in the $B_{0}$ than in the $B_2$. However, the differences in the yields between $B_{0}$ and $B_2$ were relatively great. It was probably caused by the latent B-deficiency in the $B_{0}$. Compared with white clover, the B contents of orchardgrass had relatively great differences between the $B_{0}$ and B$_2$, but both yields tended to be similar. 2. The contents of Fe, Mn, Cu, and Zn in both forages were generally different according to the forage species, whether it was a pure or mixed cultures, and additional fertilization. The effects of B application on their contents were different according to the micronutrients and above factors. 3. The Fe contents of white clover were lower in the $B_{0}$ and $B_4$ than in the$ B_2$. It tended to be related to the weak growth of roots and low yields in the $B_{0}$ and $B_2$. However, there were not consistent in the changes of contents of Mn, Cu, and Zn by the rates of B application. 4. The effects of B application on the total ion concentrations of Fe, Mn, Cu, and Zn were not consistent in both forages. However, the concentrations were generally affected by the changes in the contents of Mn and Zn. The concentrations of white clover were higher in a pure than in mixed culture.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.66-66
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• 2008

Most of the properties of ITO films depend on their substrate nature, deposition techniques and ITO film composition. For the display panel application, it is normally deposited on the glass substrate which has high strain point (>575 degree) and must be deposited at a temperature higher than $250^{\circ}C$ and then annealed at a temperature higher than $300^{\circ}C$ in order to high optical transmittance in the visible region, low reactivity and chemical duration. But the high strain point glass (HSPG) used as FPDs is blocking popularization of large sizes FPDs because it is more expensive than a soda lime glass (SLG). If the SLG could be used as substrate for FPDs, then diffusion of Na ion from the substrate occurs into the ITO films during annealing or heat treatment on manufacturing process and it affects the properties. Therefore proper care should be followed to minimize Na ion diffusion. In this study, we investigate the electrical, optical and structural properties of ITO films deposited on the SLG and the Asahi glass(PD200) substrate by rf magnetron sputtering using a ceramic target ($In_2O_3:SnO_2$, 90:10wt.%). These films were annealed in $N_2$ and air atmosphere at $400^{\circ}C$ for 20min, 1hr, and 2hrs. ITO films deposited on the SLG show a high electrical resistivity and structural defect as compared with those deposited on the PD200 due to the Na ion from the SLG on diffuse to the ITO film by annealing. However these properties can be improved by introducing a barrier layer of $SiO_2$ or $Al_2O_3$ between ITO film and the SLG substrate. The characteristics of films were examined by the 4-point probe, FE-SEM, UV-VIS spectrometer, and X-ray diffraction. SIMS analysis confirmed that barrier layer inhibited Na ion diffusion from the SLG.

• Korean Journal of Materials Research
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• v.22 no.7
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• pp.346-351
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• 2012

$Li_{1+x}Al_xTi_{2-x}(PO_4)_3$(LATP) is a promising solid electrolyte for all-solid-state Li ion batteries. In this study, LATP is prepared through a sol-gel method using relatively the inexpensive reagents $TiCl_4$. The thermal behavior, structural characteristics, fractured surface morphology, ion conductivity, and activation energy of the LATP sintered bodies are investigated by TG-DTA, X-ray diffraction, FE-SEM, and by an impedance method. A gelation powder was calcined at $500^{\circ}C$. A single crystalline phase of the $LiTi_2(PO_4)_3$(LTP) system was obtained at a calcination temperature above $650^{\circ}C$. The obtained powder was pelletized and sintered at $900^{\circ}C$ and $1000^{\circ}C$. The LTP sintered at $900{\sim}1000^{\circ}C$ for 6 h had a relatively low apparent density of 75~80%. The LATP(x = 0.3) pellet sintered at $900^{\circ}C$ for 6 h was denser than those sintered under other conditions and showed the highest ion conductivity of $4.50{\times}10^{-5}$ S/cm at room temperature. However, the ion conductivity of LATP (x = 0.3) sintered at $1000^{\circ}C$ decreased to $1.81{\times}10^{-5}$ S/cm, leading to Li volatilization and abnormal grain growth. For LATP sintered at $900^{\circ}C$ for 6 h, x = 0.3 shows the lowest activation energy of 0.42 eV in the temperature range of room temperature to $300^{\circ}C$.

• Korean Journal of Microbiology
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• v.34 no.1_2
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• pp.20-25
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• 1998

To obtain higher yield of 2,3-dihydroxybiphenyl(2,3-DHBP) dioxygenase by recombinant E. coli CK1092 carrying pcbC gene of Pseudomonas sp. P20, the environmental and physiological factors were investigated and the cultural conditions using jar fermentor were studied. E. coli CKl092 was grown in LB medium supplemented with 2% sucrose, as a basal medium. The effect of various metal ions on the enzyme production was investigated. In particular, the enzyme production increased in the presence of $Fe^{3+}$ and $Fe^{2+}$, and showed the maxium at the concentration of $10^{-5}M$. The enzyme production was increased by 55% in the medium containing $Fe^{3+}$ ($10^{-5}M$) ion. The optimal temperature and initial pH for cell growth were $37^{\circ}C$ and 7.0, respectively. In the culture using a fermentor at $37^{\circ}C$, the optimal conditions for the enzyme production were obtained at the initial pH 7.0, 1 v/v/m of aeration rate, 200 rpm of agitation speed. It was found that enzyme activity was higher when cultivated without pH control than with pH control.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.100-101
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• 2004

Many researches in Korea have been performed to understand the pollution of stream waters by acid mine drainage. However, few studies have been conducted regarding the effect of particulate and colloidal fractions on the transport of trace metals. To estimate harmful effects of trace metals, it is important to evaluate the particulate and colloidal metals as well as dissolved metals, because particulate and colloidal fractions of trace metals play an important role in transport of trace metals and may adversely affect habitats and organisms in riverine system. Colloids are solids with effective diameters in size range from 0.001 $\mu$m to 1 $\mu$m. According to Jone et al. (1974), metals in surface water, like Al, Fe, and Mn, require filtration with pore-size membranes smaller than 0.45 $\mu$m to define dissolved concentrations. The main objective of this study is to understand the effects of particulate, colloidal, and truly dissolved fractions on the transport and fate of trace metals in acid mine drainage. This study was conducted for the Onjeong creek in the Uljin mine area. Sampling was carried out in 13 sites, spatially covering the area from mine dumps to the downstream Onjeong reservoir. To examine the metal partitioning between particulate, colloidal, and truly dissolved fraction, we used successive filtration techniques consisting of conventional method (using 0.45 $\mu$m membranes) and tangential-flow ultrafiltration (using 0.001 $\mu$mm membranes). Ultrafiltration may seperate much smaller particles from aqueous phase (Josephson, 1984; Hernandez and Stallard, 1988). The analysis of metals were performed by inductively coupled plasma - atomic emission spectrometer (ICP-AES: model Perkin Elmer OPTIMA3000XL). Anions such as SO$_4$, Cl and NO$_3$ were measured with ion chromatograph (IC: model Dionex 120). Sample analysis is still in progress. The preliminary data show that the studied creek is severely polluted by Al, Fe, Mn, Pb and Zn. Toward upstream sites with relatively lower pH, less than 50% of Al and Fe occur in the sorbed form on particles or colloids, whereas more than 80% of Al and Fe occur in the sorbed form in downstream sites or tributaries with relatively higher pH. Less than 30% of Zn is present in particle or colloidal forms in the whole range of creek. Truly dissolved fraction of trace metals is negatively correlated with pH. The Kd values for Al, Fe and Zn consistently increase with increasing pH and decrease with increasing particle concentration.