• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2001.05a
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• pp.31-31
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• 2001

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.77-84
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• 2003

Structural analyses of a turbine bladed-disk for a liquid rocket turbopump are peformed to investigate the safety level of strength and vibration at design point. Due to the high rotational speed of the turbopump, effects of centrifugal forces are carefully considered in the structural analysis. Thermal load caused by extreme temperature distribution is also considered as an external force applied to turbine bladed-disk. A three dimensional finite element method (FEM) is used for cyclic symmetry structural analyses with the MSC/NASTRAN DMAP Alter. Interblade phase angles are considered to investigate structural dynamic characteristics as a function of rotational speed. Through the numerical analysis, effects of centrifugal and thermal loads on the turbine bladed-disk are examined.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.140-143
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• 2013

We investigated optimal condition for synthesis of (E)-2-hexenyl (E)-2-hexenoate (1) and (E)-2-hexenyl (Z)-3-hexenoate (2), the pheromone components of Riptortus pedestris, by Steglich esterification. The reaction with 1.1-1.5 equivalent of dicyclohexylcarbodiimide (DCC), 1.5-2.0 equivalent of (E)-2-hexenol, and 0.1 equivalent 4-dimethylaminopyrinde (DMAP) to (E)-2-hexenoic acid in toluene or (Z)-3-hexenoic acid in dichloromethane led 1 and 2 in 76-78% and 87-91% yield, respectively.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.191-197
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• 1995

The reactions of [${Mo(NO)_2Cl_2}_n$] with unidentate ligands in $CH_2Cl_2$ solvent afforded monomeric complexes [$Mo(NO)_2L_2Cl_2$]. $[Mo(NO)_2L_4](ClO_4)_2$ was obtained by reaction of unidentate with $[Mo(NO)_2L_2Cl_2]$ in aceton solvent. 4-Dimethylaminopyridine(dmap), pyridine(py), and isoquinoline(isoq) were used as coordinating ligands. These dinitrosylmolybdenum complexes are prepared and characterized by elemental analysis, $^1H$ NMR, infrared, and UV-Visible spectroscopy. The infrared spectra indicate that the NO groups occupy cis-positions of the octahedral.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.1-8
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• 2004

In this study, the method of computing and extracting the generalized unsteady aerodynamic matrices using MSC/NASTRAN and MSC/NASTRAN DMAP ALTER has been suggested for the analysis and control of aeroelastic phenomena such as flutter and gust response analysis. In addition to that, the method of approximating the generalized unsteady aerodynamic matrices using minimum state approximation method has been proposed in order to cast the aeroelastic equations of motion in state space form for aeroelastic analysis and control application. Simplified aircraft wing box model has been used for the validation of the methods suggested in this study.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.100-104
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• 2011

In this work, an optimum condition of electrolytes preparation for photovoltaic cells application was investigated experimentally in terms of impedance and conversion efficiency of the cells. 3-methoxyppropionitrie and redox pairs with LiI and $I_2$ were used as stable solvents for fabrication of electrolyte. Efficiency comparison of the prepared cells carried out for various additives and ionic liquids. From the results, there was an optimum concentration (about 0.3 M) of ionic liquids for efficient cell fabrication. For case of electrolyte using single DMAp additive, the maximum conversion efficiency of the cell was 6.4%($V_{oc}$: 0.78V, $J_{sc}$: 14.4 mA/$cm^2$, ff: 0.57). For case of electrolyte using both DMAp and CEMim additives, the maximum conversion efficiency of the cell was 7.2%($V_{oc}$: 0.79V, $J_{sc}$: 16 mA/$cm^2$, ff: 0.57). From the result of electrochemical impedance measurement, both Z1 and Z3 values of binary additives-based cell decreased compared to those of single additive-based. This is due to the decreased in internal and charge transfer resistivities of the cells.

• Journal of Embryo Transfer
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• v.14 no.3
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• pp.195-201
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• 1999

This study was carried out to improve a technique of cloned animal prodcution by preactivation of nuclear recipient oocytes with ionomycin and 6-dimethylaminopurine (6-DMAP) in rabbits. The oocytes were collected from the oviduct of superovulated rabbit at 19∼20 hours post hCG injection. The collected oocytes were preactivated and self-enucleated by treating 5 uM ionoycin for 5 min, and 2.0 mM 6-DMAP for two hours. Microsurgical removel of the chromation complex in the second polar bodies was effectively performd and single blastomere separated from 32-cell stage rabbit embryos was injected into the perivitelline space of the enculeated recipient oocyts. Follwoing electrofusion and in vitro culture for 18 hours, the nuclear transplant(NT) embryos were transferred into the uterine horns of naturally mated or synchronized recipient does. When 32 NT embryous reconstituted with preactivated oocytes were transferred to 2 recipient does, one foster doe delivered two offspring (6.3%), while not a offspring was delivered from three foster does which received 17 NT embryos reconstituted with non-preactivated oocytes. A total of 68 NT embryos reconstituted with preactivated oocytes were transferred into the uterine horns of 7 synchronized ecipient does. Among them, two recipients were pregnant and delivered three offspring(5.9%).

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.65-70
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• 2006

This study investigated apoptosis and in vitro development of parthenogenetic preimplantation porcine embryos. In vitro matured oocytes for $42{\sim}44h$ were used. Apoptotic cell death was analyzed by using a terminal deoxynucleatidyl transferase mediated deoxyuridine 5-triphosphate nick-end tabling (TUNEL) assay. In experiment 1, oocytes were activated with two electric pulses (CH) of 1.2 kV/cm for $30{\mu}sec$ (E), E + 6-dimethylaminopurine (6-DMAP) or E + cycloheximide (CH) and cultured in PZM-3 under 5% $CO_2$ in air at $38.5^{\circ}C$. In experiment 2, oocytes were activated by E and cultured in PZM-3 or NCSU-23 under a gas atmosphere of 20% $O_2$ ($5%\;CO_2$, in air) or 5% $O_2$ $(5%\;CO_2,\;5%\;O_2\;90%\;N_2)\;at\;38.5^{\circ}C$. Oocytes activated with E+6-DMAP or E+CH showed higher blastocyst rates (36.3% and 32.5%) compared to E alone (27.7%). The frequency of apoptosis according to treatments were 5.3%, 7.7% and 7.1% respectively. Oocytes activated with E alone showed lower (P<0.05) frequency of apoptosis compared to other groups. In experiment 2, parthenotes cultured in PZM-3 showed slightly higher blastocyte rates (28.2% and 29.7%) compared to NCSU-23 (22.6% and 24.4%) regardless of atmosphere. Blastocysts generated in PZM-3 showed lower (P<0.05) apoptosis rate under 20% $O_2$ (9.2% vs 16.9%), whereas those in NCSU-23 had slightly lower apoptosis rate under 5% $O_2$ (14.0% vs 18.4%). This result represents that activation method and culture condition could affect the frequency of apoptosis as well as in vitro developmental rate.

• Journal of Embryo Transfer
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• v.33 no.3
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• pp.119-127
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• 2018

The purpose of this study is to examined the electrofusion and activation conditions for the production of porcine somatic cell nuclear transfer (SCNT) embryos. In this study, immature oocytes were cultured in TCM-199 with and without hormones for 22 hours. Skin fibroblasts cells of porcine were transferred into the perivitelline space of enucleated in vitro matured oocytes. Cell fusion was performed with two different pulses that each one pulse (DC) of 1.1 kV/cm or 1.5 kV/cm for $30{\mu}sec$. After fusion subsequent activation were divided into three groups; non-treatment (control) and treatment with 2 mM 6-DMAP or $7.5{\mu}g/ml$ cytochalasin B for 4 hours. Transferred embryos were cultured in PZM-3 (Porcine Zygote Medium-3) in $5%\;CO_2$ and 95% air at $39^{\circ}C$ for 7 day. Apoptosis-related genes (Caspase-3, BCL-2, mTOR, and MMP-2) were analyzed by immunofluorescence staining. There was no significant difference between two different electrofusion stimuli in the cleavage rate; $64.9{\pm}4.8%$ in 1.1 kV/cm and $62.7{\pm}4.0%$ in 1.5 kV/cm. However, blastocyst formation rate (%) was significantly different among three different activation groups (no treatment, 2 mM 6-DMAP or $7.5{\mu}g/ml$ cytochalasin B) combined with electrofusion of 1.1 kV/cm. The blastocyst formation rate was $12.6{\pm}2.5$, $20.0{\pm}5.0$, and $34.9{\pm}4.3%$ in control, 2 mM 6-DMAP, and $7.5{\mu}g/ml$ cytochalasin B, respectively. Immunofluorescence data showed that expression levels of caspase-3 in SCNT embryos undeveloped to blastocyst stage were higher than those in the blastocyst stage embryos. Expression levels of Bcl-2 in blastocyst stage embryos were higher than those in the arrested SCNT embryos. These results showed that the combination of an electric pulse (1.1 kV/cm for $30{\mu}sec$) and $7.5{\mu}g/ml$ cytochalasin B treatment was effective for production of the porcine SCNT embryos.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.704-709
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• 1998

Non-linear optical polymer based on poly (${\alpha}$-methylstyrene-co-maleic anhydride) (MSMA) substrate polymer was prepared by polymer reaction method and its thermal and electro-optic properties were examined. In the polymer reaction between MSMA substrate polymer and 2-[4-(4-nitrophenylazo)-N-ethylphenylamino]ethanol (DR1) chromophore, the degree of substitution of DR1 into MSMA was higher with the 4-dimethylaminopyridine (DMAP) as catalyst and 3-dicyclohexyl carbodiimide (DCC) as dehydrating agent (sample, MSMA-DC) than the one with just 4-dimethylaminopyridine as catalyst (sample, MSMA-D). The synthesized NLO polymer (MSMA-DC) exhibited electro-optic coefficient of 18 pm/V (632.8 nm) and glass transition temperature ($T_g$) of about $175^{\circ}C$.