• Journal of the Korean Ceramic Society
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• v.56 no.2
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• pp.197-204
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• 2019

An electrochemical oxygen permeating membrane (OPM) is fabricated using Zr_0.895Sc_0.095Ce_0.005Gd_0.005O_2-δ (ScCeGdZ) as the solid electrolyte and aLa_0.7Sr_0.3MnO₃-bScCeGdZ composite (LZab, electrode) as the electrode. The crystal phase of the electrode and the microstructure of the membrane is investigated with X-ray diffraction and scanning electron microscopy. The electrochemical resistance of the membrane is examined using 2-p ac impedance spectroscopy, and LZ55 shows the lowest electrode resistance among LZ82, LZ55 and LZ37. The oxygen permeation is studied with an oxygen permeation cell with a zirconia oxygen sensor. The oxygen flux of the OPM with LZ55 is nearly consistent with the theoretical value calculated from Faraday's Law below a critical current. However, it becomes saturated above the critical current due to the limit of the oxygen ionic conduction of the OPM. The OPM with LZ55 has a very high oxygen permeation flux of ~ 3.5 × 10^-6 mol/㎠s in I = 1.4 A/㎠.

• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.111-114
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• 2002

This study was conducted to determine the volume of pig slurry productinn and the characteristics from 4 swine farms. For the composition of pig slurry produced, contents of N, $P_2O_5$ and $K_2O$, were 0.13, 0.25 and 0.13% in slurry, respectively. Water pollutant concentration in slurry of swine farms, $BOD_5$, $COD_MN$, SS, T-N and T-P, was $24,047mg/{\ell}$, $30,232mg/{\ell}$, $36,833mg/{\ell}$, $2,805mg/{\ell}$, $465mg/{\ell}$, respectively. The average volume of pig slurry was 6.30 ${\ell}/head/day$ and 6.32 ${\ell}$ in spring, 6.69 ${\ell}$ in summer, 6.09 ${\ell}$ in autumn, and 6.12 ${\ell}$ in winter. The average moisture content of slurry was 95.8%. The composition of slurry produced by pig farms.

• Journal of Life Science
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• v.10 no.6
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• pp.570-576
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• 2000

This study was designed to investigate the effects of mulberry (Morus alba L.) leaf extract (MLE) on oxygen radicals and their scavenger enzymes in brain membranes of rats. Sprague-Dawley (SD) male rats (160$\pm$10 g) were fed basic diet (control group), and experimental diets (MLE-100 and MLE-300 groups) added 100 and 300 mg/kg BW/day for 6 weeks. Hydroxyl radical (.OH) lecels resulted in significant decreases (13.4% and 21.1%, 12.0% and 13.4%, respectively) in brain mitochondria and microsome of MLE-100 and MLE-300 groups compared with control group. Superoxide radical ($O_2$) levels were significantly decreased about 12% in brain cytosol of MLE-300 group compared with control group. Lipid peroxide (LPO) levels were effectively inhibited (18.1% and 12.3%, respectively) in brain mitochondria and microsomes of MLE-300 groups compared with control group. Oxidized protein (OP) levels were significantly decreased (14.2%, and 10.9%, respectively) in brain mitochondria and microsomes of MLE-300 groups compared with control group. Mn-SOD activities in brain mitochondria were significantly increased (13.5% and 18.6%, respectively) in MLE-100 and MLE-300 groups, and Cu/Zn-SOD activities in brain cytosol were also effectively increased (about 17.7%) in MLE-300 groups compared with control group. GSHPx activities in brain cytosol were remarkably increased (17.2% and 23.9%, respectively) in MLE-100 and MLE-300 groups compared with control group. These results suggest that anti-aging effect of mulberry leaf extract (MLE) may play a pivotal role in attenuating a various age-related changes in brain.

• Journal of Life Science
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• v.10 no.4
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• pp.347-353
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• 2000

This study was designed to investigate the effects of silkworm (Bombyx mori L.) powder (SWP) on oxygen radicals and their scavenger enzymes in liver membranes of rats. Sprague-Dawley(SD) male rats(160$\pm$10g) were fed basic diet (control group), and experimental diets(SWP-200 and SWP-400 groups) added 200 and 400 mg/kg BW/day for 6 weeks. Hydroxyl radical (.OH) levels resulted in a consistent decreases (4.0% and 7.2%, 5.0% and 14.1%, respectively) in liver mitochondria and microsomes of SWP-200 SWP-400 groups compared with control group, and O2 radical level was significantly decreased about 12% in liver cytosol of SWP-400 group compared with control group. Lipid peroxide(LPO) levels were significantly decreased (14.4% and 9.1%, respectively) in liver mitochondria and microsomes of SWP-400 group only compared with control group. Oxidized protein (OP) levels were remarkably decreased about 12.7% and 16.3% in liver microsomes only of SWP-200 and SWP-400 groups, but significant difference between liver mitochondria could not obtained. Mn-SOD activities were remarkably increased (15.8% and 25.2%, respectively) in mitochondria of SWP-200 and SWP-400 groups, but significant difference between Cu, Zn-SOD activities in these group could be not obtained. GSHPx activity was significantly increased in liver cytosol of SWP-400 group compared with control group. These results suggest that silkworm powder may play an effective role in a attenuating a oxidative stress and increasing a scavenger enzyme activity in liver membranes.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.42-42
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• 2011

To evaluate the Hwangsu spring as natural mordants effect on dyeing. The natural mordants effect of Hwangsu spring were analyzed by pH, temperature, trace elements, organic matter and color fastness. Hwangsu spring having pH 2.42 and $14.4^{\circ}C$ was harvested at the end of September, in Yeongcheon (Gyeongbuk Province, Korea) and left on a $0^{\circ}C$ and $25^{\circ}C$ before use. Hwangsu spring during storage at $25^{\circ}C$ turned brown by photochemical reaction. The Result of ICP analysis, it contained Fe(414.9 ppm), Al(88.9 ppm), Mn(4.9 ppm) and observed character by water analysis. Dyeing and post-mordant procedure; Cotton(KS K 0905) were dyed with clove powder for 30 min at $70^{\circ}C$. Hwangsu spring, Aluminium Sulfate $14-18H_20(Al_2(SO_4)_3{\cdot}14-18H_2O)$, Iron Sulfate Heptahydrate($FeSO_4{\cdot}7H_2O$) were used by post mordant at the same ratio. The dyed fabrics were treated with 20% each mordant solution at $25^{\circ}C$ for 10min. Comparison with a reproduced chemical mordant, the K/S values of cotton fabrics dyed with Hwangsu sping were increased.

• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.123-129
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• 1999

Initial electrochemical characteristics of $LiCoO_2$ electrode for lithium ion battery with various content of super s black as conductive material were evaluated through the charge/discharge with the potential range of 4.3V to 2.0V versus $Li^+/Li^+$. The rate of C/4 and C/2 by the 3 electrode test cell composed with an electrolytic solution of 1 mol/l $LiPF_6/EC+DEC(1:3\;by\; weight)$. Lithium was used as reference electrode. High impedance charge behavior was observed at early stage of charge. In the case of $3\%w/w$ of super s black as conductive material, the specific resistance of the high impedance releasing was $3.82\;{\Omega}\;{\cdot}\;g-LiCoCo_2$ at the current density of $0.5 mA/cm^2$, which corresponds 7 times of the specific resistance of electrode $(0.728 g-LiCoO_2)$. At second charge, the specific resistance of the high impedance releasing was 63 mn · g-Lico02, which corresponds 12eio of the specific resistance of electrode and only $1.7\%$ of that of the first charge. The first charge and discharge specific capacities at C/4 rate were 160-161 and $153\~155mAh/g-LiCoO_2$, respectively, to lead $95.4\~96.4\%$ of coulombic efficiencies and ca. $6 mAh/g-LiCoO_2$ of initial irreversible specific capacity. Specific resistance at the end of charge and rest showed low value at content of super s black between 2 and $7\%w/w$, which agreed with characteristics of irreversible specific capacity. Capacity densities were reduced by the increasing the content of conductive material. They were 447 and 431mAh/ml when 2 and $2.9\%w/w$ of super s black were used, respectively, at the rate of C/4.

• Journal of Korean Society of Forest Science
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• v.37 no.1
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• pp.41-56
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• 1978

This experimentation aims to study on the characterics of tree growth by forestry land soil system and the effect of applied fertilizer by kind of tree for obtaining basic data on application of fertilizer to forestry land and to further investigate the restriction factor of tree growth by soil system for promoting more effective application of fertilizer to forestry area. 1. The characteristics of tree growth by soil system showed that tree growth was worst on erosive soil, bad on red or red and yellow soil and generally good on brown soil. 2. With regard to Black Locust, the restriction factor of its growth appeared the content of $P_2O_5$ in the soil and the less the content of $P_2O_5$ is in the soil, the worse its growth was and its growth was bad on clay soil. 3. The growth of pinus seems closely related with the content of $K_2O$ in the soil and the growth of PH was bad on neutral or alkali soil and good on weak-acid soil. Its growth greatly depended upon the content of OM or FN. 4. As Suwon Poplar is a kind of tree requiring for a special soil, its growth required for fertile soil and the content of O. MN $P_2O_5$ $K_2O$ was proportional to its growth. 5. The growth of Black Locust, pinus and Suwon Poplar was good on the soil containing much sand but bad on the soil containing much clay.

• Journal of Magnetics
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• v.9 no.1
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• pp.13-16
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• 2004

Magnetic tunnel junctions (MTJs) comprising amorphous CoNbZr layers have been investigated. $Co_{85.5}Nb_8Zr_{6.5}$(in at. %) layers were employed to substitute the traditionally used Ta layers with an emphasis given on under-standing underlayer effect. The typical junction structure was $SiO_2/CoNbZr$ or Ta 2/CoFe 8/IrMn 7.5/CoFe 3/Al 1.6 + oxidation/CoFe 3/CoNbZr or Ta 2 (nm). For both as-deposited state and after annealing, the CoNbZr-underlayered structure showed superior surface smoothness up to the tunnel barrier than Ta-underlayerd one (rms roughness of 0.16 vs. 0.34 nm). CoNbZr-based MTJs was proven beneficial for increasing thermal stability and increasing $V_h$ (the bias voltage where MR ratio becomes half) characteristics than Ta-based MTJs. This is because the CoNbZr-based junctions offer smoother interface structure than the Ta-based one.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2222-2227
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• 2007

Newly structured metal-supported solid oxide fuel cell was fabricated and characterized by impedance analysis and galvanodynamic experiment. Using a cermet adhesive, thin ceramic layer composed of anode(Ni/YSZ) and electrolyte(YSZ) was joined with STS430 metal support of which flow channel was fabricated. $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_3$ perovskite oxide was used as cathode material. Single cell performance was increased and saturated at operating time to 300hours at 800$^{\circ}C$ because of cathode sintering effect. The sintering effect was reinvestigated by half cell test and exchange current density was measured as 0.005A/$cm^2$. Maximum power density of the cell was 0.09W/$cm^2$ at 800$^{\circ}C$. Numerical analysis was carried out to classify main factors influencing the single cell performances. Compared to experimental IV curve, simulated curve based on experimental parameters such as exchange current density was in good agreement.

• Korean Journal of Materials Research
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• v.15 no.5
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• pp.301-305
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• 2005

We fabricated nickel silicide layers on whole non-patterned wafers from $p-Si(100)SiO_2(200nm)$/poly-Si(70 nm)mn(40 nm) structure by 40 sec rapid thermal annealing of $500\~900^{\circ}C$. The sheet resistance, cross-sectional microstructure, surface roughness, and phase analysis were investigated by a four point probe, a field emission scanning electron microscope, a scanning probe microscope, and an X-ray diffractometer, respectively. Sheet resistance was as small as $7\Omega/sq$. even at the elevated temperature of $900^{\circ}C$. The silicide thickness and surface roughness increased as silicidation temperature increased. We confirmed the nickel silicides iron thin nickel/poly-silicon structures would be a mixture of NiSi and $NiSi_2$ even at the $NiSi_2$ stable temperature region.