• KSBB Journal
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• v.18 no.4
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• pp.277-281
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• 2003

The study of growth characteristics for Spirulina platensis were carried out in 400 mL cylindrical photobioreactor and the effects of carbon dioxide concentration and flow rate during the growth of Spirulina platensis were investigated. The results showed that relatively low carbon dioxide concentration and high flow rate forced the growth of Spirulina platensis in experiment conditions. The pH analysis showed that different carbon dioxide concentration might form particular aqueous carbonate system in culture medium and affect the growth of Spirulina platensis. In addition, the possibility of limiting light radiation by cell density was investigated by the analysis of specific growth rate. The result intimated that the cause of decrease of specific growth rate at exponential phase was due to the limitation of light radiation by Spirulina platensis cell density in cylindrical photobioreactor.

• Journal of Embryo Transfer
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• v.16 no.1
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• pp.29-34
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• 2001

To investigate the effect of co-transfer of trophoblastic vesicle (TV) with frozen-thawed in vitro Produced (IVP) bovine embryo on pregnancy rate, IVP blastocysts were transferred to synchronized recipients. Elongated blastocysts were recovered at Day 13 to 15, and dissected more than 4 pieces to removed the embryonic disc. Throphoblastic fragments were cultured for 48 hours to make throphoblastic vesicles (TVs). TVs were cryopreserved in ethylene glycol or vitrification solution and frozen-thawed TVs were co-transferred to recipients with frozen-thawed IVP embryos. 1 The recovery rate of elongated blastocyst on Day 13 to 15 was 22.5% (18/80) and the size of recovered elongated blastocysts was 0.2∼5.0mm. 2. Eighteen elongated blastocysts were dissected into 88 pieces and 61.4% of those pieces were formed to TV (54/88) 3. The viability of frozen-thawed TV in ethylene glycol was higher than in vitrified solution (92.8% vs. 68.8%) 4. The pregnancy rate in co-transfer with frozen-thawed TV and IVP blastocyst was better than transfer only IVP blastocysts (50.0% vs. 23.1%).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.410-414
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• 2001

The microstructure, V-I characteristics, and stability of ZnO-Pr$_{6}$O$_{11}$-CoO-Cr$_2$O$_3$-Y$_2$O$_3$based vairstors were investigated with cooling rate in the range of 2~8$^{\circ}C$/min. The cooling rate relatively weakly affected the microstructure, and the varistor voltage and the leakage current in the V-I chracteristics. But the nonlinear exponent relatively strongly affected by cooling rate. And the cooling rate also greatly affected the stability for DC stress. In gross, the varistors cooled with 4$^{\circ}C$/min exhibited the highest performance in the densification, nonlinearity, and stability. Especially, they exhibited a high stability, in which the variation rate of the varistor voltage and the nonlinear exponent is -1.44% and -4.85%, respectively, under more severe DC stress such as (0.80 V$_{1mA}$9$0^{\circ}C$/12 h)+(0.85 V$_{1mA}$115$^{\circ}C$/12 h)\`(0.90 V$_{1mA}$12$0^{\circ}C$/12 h)+(0.95 V$_{1mA}$1$25^{\circ}C$/12 h)+(0.95 V$_{1mA}$15$0^{\circ}C$/12 h). It should be emphasized that the stability of these varistors is much superior to that of others.s.of others.s.

• Journal of Electrochemical Science and Technology
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• v.14 no.2
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• pp.139-144
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• 2023

In this study, carbon-coated porous nanofibers were prepared via electrospinning and the performance of Li[Ni_0.93Co_0.07]O₂ (NC) synthesized by electrospinning (E-NC) and co-precipitation (C-NC) was compared. E-NC had a discharge capacity of 206 mAh g^-1 at 0.1C (17 mA/g), which is 10% higher than that of C-NC (189.2 mAh g^-1). E-NC shows a high-rate performance of 118.32 mAh g^-1 (61.7%) at 5C (850 mA/g), which is 50% higher than that of C-NC (78.22 mAh g^-1 = 45.7%). Charge transfer of the carbon-coated porous nanofiber E-NC decreased by 35% compared to C-NC after 20 cycles as observed using electrochemical impedance spectroscopy. The results of this study show that the nanofiber structure with carbon coating shortens the Li-ion diffusion path, improves electrical conductivity, resulting in excellent rate performance.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.145-147
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• 1997

• Proceedings of the KWS Conference
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• 1998.05a
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• pp.234-238
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• 1998

• Proceedings of the KSAR Conference
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• 2001.10a
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• pp.58-58
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• 2001

This study was carried out to investigate the optimal activation condition for parthenogenetic development. In order to activate oocytes at 24 hrs post onset of maturation, the oocytes were cultured 3 - 13 μM Ca for 5 min., 5-8 ㎍/㎖ cytoclacin(CH) for 6 hrs, 0.5-2.0 mM 6-dimethylaminopurine(DMAP) for 3 hrs alone or combination. The activated oocytes were cultured in TCM-199 media at 5% CO₂, 95% N₂, 38℃. 1. The cleavage rate after 48 hrs culture of oocytes treated with 3-13 μM Ca for 5 min. were 9.6%-20.0% and 3.8-7.3%, respectively. When oocyte were treated with 10 μM Ca, the blastocyst formation rate was significantly higher than other group. 2. The cleavage rate after 48 hrs culture of oocytes treated with 5-8 ㎍/㎖ cytoclacin(CH) for 6 hrs, were 9.4%-21.8% and 0.0-7.3%, respectively. When oocyte were treated with 10㎍/㎖ CH, the blastocyst formation rate was significantly higher than other group. 3. The cleavage rate after 48 hrs culture of oocytes treated with 0.5-2.0 mM 6-dimethylaminopurine(DMAP) for 3 hrs were 9.1%-21.8% and 0.0-7.3%, respectively. When oocyte were treated with 2.0mM DMAP, the blastocyst formation rate was significantly higher than other group. 4. The cleavage rate after 48 hrs culture of oocytes treated with Ca＋CH, Ca＋DMAP, CH＋DMAP were 75.9%-93.5% and 9.7 -13.3%, respectively. When oocytes were treated with Ca followed by DMAP, the blastocyst formation rate was significantly higher than other group(p〈0.05). 5. When necleus transferred embryos co-cultured with BSA, EGF and CS, the developmental rate to blastocyst were higher than control group.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.585-590
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• 2003

Cobalt oxygen carrier complex N,N'-ethylenebis(3-methoxysalycylideneiminato)cobalt(II), Co(3MeOsalen) was prepared at $25{\circ}C$. UV and visible absorption spectra of the complex and hydrazobenzene were studied in non-aqueous solvent methanol in the range of wavelength 200-600 nm. The oxidation of hydrazobenzene by oxygen in non-aqueous solvent is catalysed by Co(3MeOsalen). In the presence of triphenylphosphine($PPh_3$), the rate decreases in methanol. This is presumably attributable to the coordination of $PPh_3$ to the Co(3MeOsalen), resulting in the catallytically inactive compound. The initial rates of the oxidation of hydrazobenzene with the ligand triphenylphosphine were measured by the theoretical values of the rates, Rate=$k_1+k_2K_1[P]/1+K_1[P]+K_1K_2[P]^2$. This fact would be a poorer σ-donor ligand than methanol.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.165-172
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• 2014

Experiments were conducted to identify basic characteristics of $CO_2$ capture using a spray tower with a single nozzle. Results were evaluated in terms of $CO_2$ saturation which is the main determining factor of regeneration energy, and capture efficiency under various operating conditions. Changes in the capture efficiency under various conditions are well expressed as a monotone increasing function of the relative solvent $(NH_3):CO_2$ flow rate. Although changes in $CO_2$ saturation are also well described as a function of the $NH_3/CO_2$ flow rate ratio, these are expressed as a monotone decreasing function, in contrast with the increasing function of $CO_2$ efficiency. In recent research on the relationship between $CO_2$ saturation and capture efficiency, $CO_2$ saturation was found to decrease when capture efficiency increased. In conclusion, the results show that the amount of solvent used for achieving high capture efficiencies is excessive, as is the amount of regeneration energy needed.

• Korean Journal of Acupuncture
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• v.22 no.3
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• pp.137-156
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• 2005

Objectives : Cnidium officinale(CO) has been used for medication for stroke in the Oriental Medicine. So this study was planned to investigate the effects of CO on the focal ischemia-induced by Middle Cerebral Artery Occlusion(MCAO) in rats Materials and methods : The focal ischemia was induced by MCAO. CO extracts through oral administration and herbal acupuncture at GB2l was carried out during 3 weeks after focal ischemia-induced. Eight-arm radial maze was used for the behavioral task. For the neuroprotective effect of CO, we investigated AchE, ChAT, and NGF-expression by immnohistochemical method. Results : The error rate in the eight-arm radial maze task was significantly decreased in normal group compared to control group on 1-6days, OA-CO1(CO oral administration, 0.8g/kg) group on 1-6days, OA-CO2(CO oral administration, 1.6g/kg) group on 1-3,5,6days, HA-CO1(CO herbal acupuncture, 0.016g/kg) group on 2,3,6days, HA-CO2(CO herbal acupuncture, 0.008g/kg) group on 1-3,5,6days. The rate of correct choice was significantly increased in OA-CO1, HA-CO2. The density of neurons in the hippocampal CA1 was the most increased in OA-CO1, HA-CO1, HA-CO2. The density of ChAT in the hippocampal CA1 was increased in OA-CO1, HA-CO2. The density of ChAT in the hippocampal CA1 was significantly increased in OA-CO1, HA-CO2. The density of NGE in the hippocampal CAI was significantly increased in OA-CO1, OA-CO2, HA-CO2. Conclusions : These results suggest that CO oral administration with 0.8g/kg and CO herbal acupuncture with 0.008g/kg might be used as a regulator of cell death of cholinergic system induced by stroke.