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        검색결과 43

        21.
        2011.09 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to examine effect of ethylene glycol for semen cryopreservation in Korean Jeju Black Bull. The semen was cryopreserved with extenders containing cryoprotectants (7% glycerol and 3%, 5%, 7% ethylene glycol) and packed to 0.5 ml straws. The semen straws were located above 3 cm of liquid nitrogen for 5 min, 5 cm for 10 min and 8 cm for 10 min. And then frozen straw was plunged into LN2. Post-thawed sperm motility, viability and membrane integrity were significantly higher in 5% ethylene glycol (72.5±5.00%, 54.88±0.66% and 46.00±2.40%; p<0.05). Motility and viability were similar between 7% glycerol and 5% ethylene glycol. However, the membrane integrity was significantly higher in 5% ethylene glycol (34.69±4.64% vs 46.00±2.40%; p<0.05). The viability and membrane integrity were significantly higher in 5 cm for 10 min and 8 cm for 10 min than 3 cm for 5 min (viability: 55.81±2.94, 55.19±3.34 vs 47.94±3.48%; p<0.05 and membrane integrity: 44.94±3.51, 46.06±2.25 vs 40.38±1.03%; p<0.05). The percentage of capacitated sperm assessed by CTC staining, percentage of F pattern was higher in 7% glycerol, 5% and 7% ethylene glycol, and AR pattern was significantly higher in 3% ethylene glycol. F pattern was significantly increased in 5 cm for 10 min and 8 cm for 10 min (p<0.05), but AR pattern was significantly increased in 3 cm for 5 min (p<0.05).
        4,000원
        22.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Cu nanofluid in ethylene glycol was prepared by electrical explosion of wire, a novel one-step method. The X-ray diffraction, field emission scanning electron microscope and transmission electron microscope were used to study the properties of Cu nanoparticles. The results showed that the nanoparticles were consisted of pure face-centered cubic structure and near spherical shape with average grain size of 65 nm. Ultraviolet-visible spectroscopy (UV-Vis) confirmed Cu nanoparticles with a single absorbance peak of Cu surface plasmon resonance band at 600 nm. The nanofluid was found to be stable due to high positive zeta potential value, +51 mV. The backscattering level of nanofluid in static stationary was decreased about 2% for 5 days. The thermal conductivity measurement showed that Cu-ethylene glycol nanofluid with low concentration of nanoparticles had higher thermal conductivity than based fluid. The enhancement of thermal conductivity of nanofluid at a volume fraction of 0.1% was approximately 5.2%.
        4,000원
        23.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        다공성 Poly(propylene) 분리막의 지지 하에 전해질 용액 (EC/DEC 1 : 1 혼합물 내의 LiPF6 1 M 용액) 내에서 DEGDMA [Di(ethylene glycol) dimethacrylate]의 70℃ 열중합을 통하여 겔 고분자 전해질(GPE)막이 합성 되었다. 합성된 겔 고분자 전해질막의 이온전도도 및 전기화학적 안정성은 AC 임피던스법 및 CV (cyclic voltametry)법에 의하여 측정 평가하였다. 겔 고분자를 전해질로, 그리고 양극 및 음극으로는 각각 LiMi0.8Co0.2O2 및 graphite로 이용하여 리튬이온전지(LIB)도 제작하였다. 열중합을 통하여 리튬 이온전지에 적합한 이온전도도(10 -3 S/cm 이상) 및 전기화학적 안정성을 보이면서 자체적인 성상을 유지하는 겔 고분자 전해질막을 얻을 수 있었다. 단량체 함량 5%의 전구체로 제작한 겔 고분자 전지는 단량체 함량이 7.0% 및 10.0%인 경우에 비하여 우수한 고율 및 충-방전 효율을 보였다.
        4,000원
        24.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present work, ethylene glycol-based (EG) copper oxide nanofluids were synthesized by pulsed wire evaporation method. In order to explode the pure copper wire, high voltage of 23 kV was applied to the both ends of wire and argon/oxygen gas mixture was used as reactant gas. EG-based copper oxide nanofluids with different volume fraction were prepared by controlling explosion number of copper wire. From the transmission electron microscope (TEM) image, it was found that the copper oxide nanoparticles exhibited an average diameter about 100 nm with the oxide layer of 2~3 nm. The synthesized copper oxide consists of CuO/ phases and the Brunauer Emmett Teller (BET) surface area was estimated to be . From the analyses of thermal properties, it is suggested that viscosity and thermal conductivity of EG-based copper oxide nanofluids do not show temperature-dependent behavior over the range of 20 to . On the other hand, the viscosity and thermal conductivity of EG-based copper oxide nanofluids increase with volume fraction due to the active Brownian motion of the nanoparticles, i.e., nanoconvection.
        4,000원
        25.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, block copolymer of polystyrene and polyethylene glycol methyl ether methacrylate(PEGMA) by ATRP(atom transfer radical polymerization) method was synthesized. 4 arm-molecule which contained halogen atom was synthesized for an initiator. With 4 arm-molecule monodispered polystyrene were synthesized by ATRP method. The molecular change of synthesized monodispersed polystyrene with respect to time was investigated and living polymer characteristic was confirmed. Block copolymer of polystyrene and polyethylene glycol methyl ether methacrylate(PEGMA) was synthesized by ATRP with macroinitiator which was synthesized from the monodispersed polystyrene(Mn=12000). The molecular weight of obtained PS-b-PEGMA was 22,000.
        4,200원
        26.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 기존의 이차전지의 분리막보다 좋은 성능으로 각광받고 있는 PVdF (poly(vinylidene fluoride))에 공극률을 높여 전지의 성능을 향상시켜주는 수용성 고분자인 PEG (Poly(ethylene glycol))를 첨가하여 충전용 리튬 이차전지의 분리막을 상전이 방법으로 제조하였다. 용매인 DMF (N,N-dimethylformamide)에 PVdF-PEG를 단일상으로 녹인 후 깨끗한 유리판에 캐스팅하여 막을 얻었다. 기공은 증류수로 채워진 응고조에서 용매-빈용매 교환으로 형성되어진다. 주사전자현미경(scanning electron microscopy, SEM)을 이용하여 분리막의 단면 관찰을 통해 다공성을 확인하였고 UTM (universal testing machine)을 이용하여 기계적 물성을 확인하였다. PEG-10의 정체시간 30 s에서 균일한 스폰지 구조를 확인할 수 있었으며, 이는 87%의 뛰어난 공극률을 가지며 인장강도의 경우 PEG-10에서 3.72 MPa로 가장 크게 나타났고, 신장률과 모듈러스 부분에서도 역시 75.45%와 275.27 MPa로 뛰어난 성능을 나타냈다.
        4,000원
        29.
        2006.04 구독 인증기관·개인회원 무료
        Several titanate powders (, etc.) were synthesized by an ethylene glycol solution route. Titanium isopropoxide and nitrate salts were dissolved in stoichiometric proportions in liquid-type ethylene glycol without any precipitation. The parent precursor sols were dried to porous gels, and then the gels were calcined and crystallized. All synthesized titanate powders had stable crystallization behavior at low temperature and high specific surface area after a simple ball-milling process. A three-component PZT powder was also synthesized successfully by the ethylene glycol method. In this study, the characteristics of the multi-component titanate powders by the ethylene glycol method are examined.
        30.
        2004.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이산화탄소 분리에 이용하기 위하여 PEG (Poly(ethylene glycol)diacrylate)와 PPG (Poly(propylene glycol) diacrylate)를 광학 중합반응(Photopoly merization)을 이용하여 제조하였다. PEG와 PPG는 분자량이 각각 258과 540이었다. PEG와 PPG의 질량 혼합비(wt%)를 9:1, 8:2, 7:3, 6:4, 5:5로 변화시키면서 막을 제조하였다. 25^℃에서 PEG/PPG (9:1)의 이산화탄소 투과도는 28.9 barrel 으로 나타났으며, 선택도(PCO_2/PN_2)는 57.9로 나타났다. 같은 온도에서 PEG/PPG(5:5)로 조성을 변화시켰을 때 이산화탄소 투과도는 40.4 Barrer, 기체선택도(PCO_2/PN_2)는 51.8를 나타냈다 이산화탄소의 투과도는 5:5 > 6:4 > 7:3 > 8:2 > 9:1의 경향을 나타내었다. 35^℃로 승온을 하는 경우에 PEG/PPG (9:1)는 45.4 Baller, 선택도(PCO_2/PN_2)는 48.2을 나타냈으며, PEG/PPG (5:5)의 이산화탄소 투과도는 78.9 Barrer을 나타내고 선택도(PCO_2/PN_2)는 33.2로 나타났다. 각각의 온도에서 이산화탄소의 기체선택도(PCO_2/PN_2)는 PPG의 함량이 증가하면서 감소하는 경향을 나타내었다
        4,000원
        32.
        2002.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pure and fine, two-component titanate powders (barium titanate, calcium titanate etc.) were synthesized by an ethylene glycol method. Titanium isopropoxide and other metal ionic salts were dissolved in liquid-type ethylene glycol without any precipitation. In non-aqueous system, the amount of ethylene glycol affected the solubility and homogeneity of metal cation sources in the solution. At the optimum amount of the polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. Most of the synthesized powders had sub-micron or nano-size primary particles after calcination and the agglomerated calcined powders were easily ground by ball milling process. All synthesized titanate powders had stable crystallization behavior at low temperature and high specific surface area after ball milling. The crystallization behavior and the microstructures of the calcined powders were affected on the ethylene glycol content.
        4,000원
        34.
        1994.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present experirnents on cryopreservation were carried out to investigate effect of solution toxicity, equilibration time and cell stages on the post-thaw survival of mouse morulae and blastocyst embryos cryopreserved by vitrification in EFS solution. The mouse embryos were exposed to the EFS solution in one step at room temperature, kept in the EFS solution during different period for toxicity test, vitrified in liquid nitrogen and thawed rapidly. After the mouse morulae embryos were exposed to EFS solution for 2 and 5 ruin. at room temperature and then they were washed in 0.5 M sucrose solution and basal mediurn(D-PBS + 10% FCS), they were cultured to examined cryoprotectant toxicity induced injury during exposure, most of embryos developed to expanded blastocysts(100 and 90.0%). However, when the exposure time was extended to 10 and 20 min, these development rates dropped dramatically in 10 ruin. (75.0%) and 20 ruin. (4.5%), respectively. When the compacted morulae were vitrified in EFS solution after equilibration for 2 and 5 min, the embryos have developed to normal blastocyst following thawing, washing and culture processes was 89.3 and 89.6%. However, when the exposure time was expanded to 10 ruin, this survival rate dropped to 68.8%. When the blastocyst were vitrified in EFS solution after equilibration for 2, 5 and 10 minutes, the survival rate of embryos which developed to normal blastocyst following thawing and culture processing were 58.5, 46.7 and 22.4%, respectively. The optimal time of equilibration of mouse morula and blastocysts in EFS solution seemed o be 2 and 5 ruin.
        4,000원
        35.
        1993.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The post-thaw survival of mouse embryos of the various developmental stages was determined after cryopreservation by vitrification in a solution containing ethylene glycol, Ficoll and sucrose (EFS). All the embryos were equilibrated for 2 minutes just prior to freezing. The number of blastomeres during in vitro development was counted by nuclei higher rates of post-thaw survival were obtained from the embryos of 2-cell(92.2%), 8-cell(77.2%) or morula stage(90.0%) than those of blastocyst stage(62.7%). The number of blastomeres per embryo following in vitro culture for 24 hours was significantly(P<0.05) smaller as 66.0f22.3 in vitrified and thawed morulae than fresh morulae(91.712.2).
        4,000원
        36.
        1993.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Transesterification reaction between dimethyl phthalate and ethylene glycol was kinetically investigated in the presense of various metal nitrate catalysts at 170℃. The reaction rates measured by the amount of distilled methanol from the reaction vessel. The transesterification reaction was carried out under the first order conditions respect to the concentration of dimethyl phthalate and catalyst, respectively. The over all order was 2nd. By Arrhenius plot, the activation energy was calculated as 17.4kcal/mole and 17.2kcal/mole on the transesterification reaction with zinc nitrate and lead nitrate, respectively. Apparent rate constant, k' was appeared linear about concentration of catalyst.
        4,000원
        37.
        2015.04 서비스 종료(열람 제한)
        Currently, a technique to subdivide the process refining is introduced, can be divided into the steel slag. In this study, Free-CaO in the electric arc furnace slag by the ethylene glycol method for the quantitative analysis for the expansion to proceed with construction materials.
        38.
        2013.10 서비스 종료(열람 제한)
        Blast furnace slag is recycled as high value-added material, while steel slag is difficult to recycle or is recycled as low value-added one relatively due to its expansion collapsability. It's property is caused by the high content of Free-CaO and unstable steel oxides. Currently, a technique to subdivide the process refining is introduced, can be divided into the electric furnace steel slag and reducing steel slag. In this study, Free-CaO in the electric arc furnace slag by the ethylene glycol method for the quantitative evaluation for the expansion to proceed with construction materials, electric arc furnace slag oxidation is to use.
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