• 한국가축번식학회지
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• 제11권2호
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• pp.122-126
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• 1987

This study was carried out to investigate the effects of the glycerol equilibration methods and embryo grades before freezing on the survival rate after thawing in mouse embryos. The results obtained from this study were as follows: 1. The number of embryos of grade I(Excellent), II(Good) and III(Fair) before freezing in this study was 97(27.4%), 160(45.2%) and 97(27.4%), respectively. 2. The average survival rate of frozen-thawed embryos in 3 and 5 steps glycerol equilibration was 66.7% and 64.1%, and the rate of transfererable embryos after culture was 68.9% and 69.0%, respectively. 3. Out of embryo grade I and II before freezing, the transferable rate after thawing was 75.2% and 48.1%, respectively, and grade I embryos before freezing was higher transferable rate than that of grade II.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.60-77
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• 1992

The effects of exhaust gas recirculation(EGR) on the characteristics of exhaust emissions and specific fuel consumption have been investigated using an eight-cylinder, four cycle, direct injection diesel engine operating at several loads and speeds. The experiments in this study are conducted on the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. In conclusion, it is found that $NO_{x}$ emission is markedly reduced with the drop of burnt gas temperature at high speeds and loads especially as the EGR rate increases, while the soot particulate rises with EGR rate and load at a given engine speed, especially high loads. The reduction of exhaust emissions within the Korea heavy duty diesel engine emission standards can be roughly achieved by the optimal EGR rate without degarding the specific fuel consumption, based on the correlations between exhaust emissions.

• 말소리와 음성과학
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• 제8권3호
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• pp.79-90
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• 2016

The purpose of this study was to investigate the effects of stuttering severity on articulation rate measured from different types of utterances in preschool children who stutter. Participants were 40 boys who stutter (CWS) and age-matched 10 boys who do not stutter (CWNS). CWS were sub-grouped based on the severity of their stuttering: 15 mild, 13 moderate, and 12 severe. Utterances were categorized as "overall utterance" including all utterances that children spoke and "fluent utterance" which did not contain any disfluencies. Utterances containing abnormal disfluencies were categorized as "SLD utterance" for CWS. The results revealed no significant difference among groups in any type of utterance. There were significant positive correlations in articulation rates between utterance types. Stuttering severity was not a factor for characterizing the articulation rate of each type of utterance. Also, current findings suggest that articulation rate may not predict speech motor control ability in preschool CWS.

• 한국음향학회지
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• 제22권1호
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• pp.14-22
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• 2003

본 연구는 발화속도에 따른 한국어 모음의 음향적 특성에 관한 것으로 보통, 느림. 빠름의 발화속도 변화에 따라 단모음과 이중모음의 반모음 성분과 단모음성분의 지속시간적 특성과 포만트 특성을 살펴보았다. 지속시간은 전체적으로 발화속도가 빨라짐에 따라 짧아지는 경향을 보였으나 포만트는 단모음과 이중모음의 단모음 성분의 경우 큰 차이가 없었고 이중모음의 반모음 성분의 경우는 반모음의 종류에 따라 서로 다른 결과를 보여주었다.

• 한국가축번식학회지
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• 제18권1호
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• pp.31-37
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• 1994

This study carried out to investigate the effects of cryoprotectants in the medium on the survival rate of rapidly frozen porcine bisected demi-embryos. The porcine bisected demi-embryos following dehydration by cryoprotectants containing sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water bath. Survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows : 1. The survival rates of without-zona pellucida embryos and 2 blastomeres porcine embryos were 10.0 and 7.1%, respectively. The rate of unfrozen blastomeres (20.00%) was significantly higher than that of non-frozen oocytes. 2. The survival rates of with and without-zona pellucida of bisected porcine embryos by micromanipulator were 20.0 and 14.3%, respectively. 3. The developmental rates of with and without-zona pellucida of bisected poricine embryos by micromanipulator were 13.3 and 7.1%, respectively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.928-932
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• 1996

Single overload fatigue tests with overload sizes ranging from 50% and 100% have been performed to investing ate the fatigue crack growth retardation behavior. A modified and experimental method of Willenborg's model for prediction of crack growth retardation behavior has been developed, based on evaluations of equivalent plastic zone size (EPZS) changing its size along the overload plastic zone boundary. The minimum crack growth rates of each overload size are linearly decreased with overload size increasing, but fatigue lives extended by single overload are increasing much more unlike the crack growth rates. Comparisons of crack growth behavior predicted by EPZS model and Willenborg model have shown that the EPZS model accounts for overload effects better than Willenborg model. These effects include delayed retardation, large retardation region, minimum crack growth rate, and the increase rate of crack growth rate in the region crack growth rate recovered.

• Journal of Ginseng Research
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• 제19권1호
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• pp.1-16
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• 1995

Effects of Korean red ginseng (KG) and western ginseng (WG) on body temperature, pulse rate, clinical symptoms and hematological changes in human were studied after administration p.o. with Korean red ginseng and western ginseng for 10-days. KG was more effective in keeping homeostsis in than western ginseng in the changes of body temperature and pulse rate. KG was more effective in low body temperature and SOEVMIN (소음인), while inducing tachycardia especially in SOYANGIN (소양인) and TAEEUMIN (태음인). WG tended to drop temperature abruptly and also descended pulse rate with greater range than KG. KG and WG could cause side effects such as headache and gastrointestinal syndromes and induce hypertension or hypotension abruptly in specific constitutions. However, KG and WG did not cause abnormal changes in urinalysis and hematology.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.1017-1021
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• 1997

Solvolyses of p-methoxyphenyl chloroformate in water, D2O, CH3OD, 50% D2O-CH3OD, and in aqueous binary mixtures of acetone, ethanol and methanol are investigated at 25.0 ℃. Product selectivities are reported at 25 ℃ for a wide range of ethanol-water and methanol-water solvent compositions. The Grunwald-Winstein plots of first-order rate constants for p-methoxyphenyl chloroformate with YCl (based on 1-adamantyl chloride) show marked dispersions into three separate curves for the three aqueous mixtures with a small m value and a rate maximum for aqueous alcohol solvents. Third-order rate constants, kww, kaw, kwa and kaa were calculated from the observed kww and kaa values together with kaw and kwa calculated from the intercept and slope of the plot of 1/S vs. [alcohol]/[water]. The calculated rate constants, kcalc and mol % of ester agree satisfactorily with those of the observed rate constants, kobs and mol % of ester, supporting the stoichiometric solvation effect analysis. The kinetic solvent isotope effects determined in water and methanol are consistent with the proposed mechanism of the general base catalyzed carbonyl addition-elimination.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.129-136
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• 2003

Numerical study with momentum-balanced boundary conditions has been conducted to grasp chemical effects of added $CO_{2}$ and $H_{2}O$ to fuel- and oxidizer-sides on flame structure and NO emission behavior in $CH_{4}$/Air counterflow diffusion flames. The dilution with $H_{2}O$ results in significantly higher flame temperatures and NO emission, but dilution with $CO_{2}$ has much more chemical effects than that with $H_{2}O$. Maximum reaction rate of principal chain branching reaction due to chemical effects decreases with added $CO_{2}$. but increases with added $H_{2}O$. The NO emission behavior is closely related to the production rate of OH, CH and N. The OH radical production rate increases with added $H_{2}O$ but those of CH, N decrease. On the other hand the production rates of OR CH and N decrease with added $CO_{2}$. It is found that NO emission behavior is considerably affected by chemical effects of added $CO_{2}$ and $H_{2}O$.

• Journal of Radiation Protection and Research
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• 제26권4호
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• pp.347-356
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• 2001

Guarana, a tropical plant is found in powdered for in health food and is very popular soft drink in Brazil as an energy feaster with its high caffeine contents. We examined its radioprotection effects during organogenesis stages of ICR mice by malformations rate and cellular lead 8 the embryo by radiation and analyzed the mechanism of the radioprotection effects in the fetal of ICR mice. The results of this study showed that Guarana reduced clearly the embryonic death rate and teratogenesis rate by radiation. Its radioprotection effect inject be related with its radioprotection effect might be related with its antioxidant effect or free radical scavenger. We need to exposure the Guarana as a potential radioprotection agent. Therefore, we investigated about radiation effects by Guarana using to mice experiments in this paper.