• Journal of Nutrition and Health
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• v.8 no.2
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• pp.31-36
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• 1975

Relative retarding or pro-oxidant effect of 0.02% BHT, 0.01% citric acid and 0.1 ppm $CuSO_4$ $5H_2O$, on the peroxide value and the free fatty acid value development of two groups of edible soybean osils was studied. One group of the oils was stored in a dark place at $40{\pm}0.5^{\circ}C$, and the other group was irradiated 3 hours daily, with direct sunlight. The results of the study were as follow; 1. Peroxide value and free fatty acid value were, in general, more rapidly promoted in the case of the irradiated oils than in case of the oils stored in the dark place. 2. Peroxide value and free fatty acid value were rapidly increased in the case of the sample in addition to $CuSO_4$ $5H_2O $ in both caies. 3. Synergistic effect of citric acid on BHT was strong pronounced in both cases.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.463-463
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• 2011

농업은 다른 산업과 달리 원천적으로 기후 조건과 변화에 크게 좌우되는 분야로, 기후변화로 인한 영향에 가장 민감한 분야이다. 안정적이고 지속적인 농작물 생산을 위해서는 기후변화가 농업수자원에 미치는 영향에 대하여 정확히 파악하고, 이로 인해 발생할 수 있는 부정적 효과를 최소화하기 위한 연구가 필요하다. 즉 기온 상승, 강수량 및 강우강도 변화 및 일조시간의 변화 등의 기후변화에 따른 농업수자원에 미치는 영향에 대한 평가가 필요하다. 기후변화가 관개용수에 미치는 영향은 기온 상승과 강수량 증가로 크게 나누어 볼 수 있다. 기온상승은 증발산량 증가로 이어져 관개용수 증가의 원인이 된다. 강수량의 증가는 관개용수를 감소의 원인이 될 수 있지만, 계절별 강우 편차 및 강우 강도의 변화는 유효우량의 감소의 원인이 될 수 있다. 이는 관개기의 농업용수의 안정적 공급과 관리의 어려움이 예상되어 결과적으로 농업용수의 안정성을 위협받을 수도 있다. 즉, 전체 수자원에 큰 비중을 차지하고 있는 논벼의 순용수량에 있어서 기후변화가 미치는 영향에 대한 연구가 필요하다. 또한 농업용수개발과 수자원의 효율적인 관리계획 수립을 위해서는 기후변화에 따른 농업용수 수요분석이 이루어져야 한다. 따라서 본 연구에서는 기후변화 시나리오에 따른 순용수량을 산정하고, 이를 빈도분석하여 논벼의 수요량 변화를 분석하고자 하였다. 이를 위하여 이를 위하여 먼저 CGCM3.1 (Coupled Global Climate Model Ver. 3.1) 및 LARS-WG (Long Ashton Research Station Weather Generator)를 이용하여 2011년부터 2100년까지의 A1B, A2 및 B1 시나리오별로 기상자료를 생성하였다. 이를 바탕으로 물수지 방법을 이용하여 논에서의 순용수량을 산정하고, 한발기준 10년빈도 순용수량을 산정하여 논벼의 수요량을 분석하였다. 연구 결과는 향후 기후변화로 인한 농업용수 변화를 파악하고 전망함으로써, 추후 발생할 수 있는 부정적 효과를 최소화하기 위한 대응 전략 및 농업수자원 정책의 기초 자료로 활용될 수 있을 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• v.39 no.3
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• pp.206-212
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• 2011

It was investigated the hardness and dimensional stability of heat-compressed wood by compression temperature and time. The surface hardness of heat-compressed wood increased with increasing compression temperature. The lowest hardness value (5.0 N/$mm^2$) was observed in the temperature $70^{\circ}C$ while the highest value (15.6 N/$mm^2$) was obtained in compression temperature $220^{\circ}C$. Dimensional recovery test results showed that fixation of compression set improved with increasing compression temperature. However, the fixation effects were negligible by press time. Contact angle increased with increasing press temperature and time.

• Korean Journal of Materials Research
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• v.8 no.8
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• pp.707-713
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• 1998

The influence of plasma carburizing process on the surface hardness of SCM415 low-alloy steel (0.15% C) was investigated under the various process conditions of gas composition. gas pressure, plasma current density. temperature and time. The effective case depth was found to depend on the amount of methan gas containing carbon. thus the deepest case depth and the uniform hardeness were obtained with the 100% methan gas. The case depth increased with the plasma current density. The effective plasma carburizing temperature of SCM415 steel was found to be higher than 85$0^{\circ}C$, and the case depth was proportional to the square root of carburizing time under the same current density. The bending fatigue strength of the plasma carburized specimen is' higher than those of as- received specimen or reheat-quenched specimen.

• The Korean Journal of Physiology
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• v.22 no.1
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• pp.101-109
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• 1988

최근에 마취한 흰쥐에서 중뇌망상체를 전기적으로 자극하면 췌장의 외분비 기능이 증가하며 이러한 결과는 망상체의 자극으로 인하여 교감신경계의 활성도가 상승하기 때문이라는 보고가 있다. 한편 교감신경계의 활성도가 상승할 경우 교감신경계의 전달 물질인 catecholamine이 교감신경 종말 뿐만 아니라 부신수질에서도 유리된다고 알려져 있다. 그러므로 본 연구에서는 중뇌망상체의 자극으로 인하여 췌장의 외분비 기능이 증가함에 있어 교감신경계가 중요한 역할을 담당하는지를 확인하고, 이때 부신수질이 관여하는가를 알아보고자 하였다. 마취한 흰쥐에게 atropine (1mg/kg) 또는 reserpine (5mg/kg)을 투여하거나 또는 부신을 적출한 다음 중뇌망상체를 전기 자극하면서 췌장액을 채취하였다. 사용한 전기자극의 매개변수는 1.3V, 40Hz, 2msec이었다. atropine과 reserpine을 투여하면 마취한 흰쥐의 자발적 췌장액 분비량과 단백질 분비량은 모두 유의하게 감소하였으나 부신을 제거하면 췌장액 분비량에는 이렇다할 변동이 없는 반면에 단백질 분비량은 유의하게 감소하였다. 중뇌망상체를 전기자극하면 췌장액 분비량과 단백질 분비량 모두가 유의하게 증가하였다. 이러한 망상체의 자극효과는 atropine 전처치에 의하여 이렇다할 영향을 받지 않았으나 reserpine 전처치에 의하여 소실되었다. 그러나 부신을 적출하면 망상체 자극에 의한 췌장액 분비량의 증가는 유지되는 반면에 단백질 분비량의 증가는 소실되었다. 한편 미주신경을 절단한 흰쥐에서 중뇌망상체를 자극하는 동안에 경동맥의 수축기 및 이완기 혈압이 상승하였는데 이러한 망상체의 자극효과도 reserpine의 투여에 의하여 유의하게 감소되었다. 본 실험의 결과를 종합하여 보면 마취한 흰쥐에서 중뇌망상체의 자극은 교감신경계를 활성화시켜 췌장액 분비량과 단백질 분비량에 촉진적인 영향을 미치며, 이때 활성화된 교감신경계는 부분적으로 부신을 경유하게 췌장의 단백질 분비에 촉진적인 영향을 미치는 것으로 생각된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.6
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• pp.419-423
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• 2015

The flowing caused by artificial upwelling structure occurs ascending water flowing and vortex of rear side. In this moment, plentiful nutrient in the bottom water moves to the surface of the water and makes those plankton and fishing ecology promoted so that the fishing productivity can be enhanced. In this study, the changes of the upwelling flowing is included in consideration of the conditions of stratification by using CFD. In the conclusion, the closer upwelling effect is from the artificial upwelling structure, the better effectiveness comes out. Regardless of the conditions of stratification, only the upwelling feature from the bottom to the surface was shown up. But considering the conditions of stratification, the repeated flowing feature between upwelling and downwelling was verified.

• International Area Studies Review
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• v.20 no.1
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• pp.3-22
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• 2016

In this study, I examine mutual shock spillover effects among interest rate differences, won-dollar foreign exchange change rates, and stock market returns in Korea during the daily sample period from the beginning of 1995 to the October 16, 2015, using the multivariate GARCH (generalized autoregressive conditional heteroscedasticity) BEKK (Baba-Engle-Kraft-Kroner) model framework. Major findings are as follows. Throughout the 6 model estimation results of variance equations determining return spillovers covered from symmetric and asymmetric models of total sample period and two crisis sub-sample periods composed of Korean FX Crisis Times and Global Financial Crisis Times, shock spillovers are shown to exist mainly from stock market return shocks. Stock market shocks including down-shocks from the asymmetric models are shown to transfer to those other two markets most successfully. Therefore it is most important to maintain stable financial markets that a policy design for stock market stabilization such as mitigating stock market volatility.

• Land and Housing Review
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• v.13 no.1
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• pp.39-54
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• 2022

Using the 1st to 13th rounds of occupational history data of the Korea Employment Information Service's Youth Panel (YP2007), this study explores the trends and characteristics of the youth labor market in Seoul. We further empirically investigated the job duration and wage determinants of youth employed in Seoul. The results confirm that workers who have a higher income and a higher consistency with their majors are less likely to leave. In addition, we find that workers in full-time, householders, or labor unions have a higher income if they are men and work in large companies. In particular, compared to the reference group (appropriate academic background, appropriate skill), mismatches in the lack of education and skill showed a wage increase effect of 4.9% and 5.5%, respectively. For the major consistency, the wage of the matched major group is 3.8% higher than the non-matched major group.

• Journal of Labour Economics
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• v.40 no.1
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• pp.37-68
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• 2017

This study analyzes the relationship between household debts and married female's labor supply. For doing this we construct effective interest rate faced by each household using interest paid amount and household financial debt amount. The effective interests rate for the households which have no financial debt are estimated by Heckman Selection model. The estimation results show that the increase in effective interest rate has led to the expansion of married women's the labor market participation. This suggests a possibility that negative scenarios resulting from an increase in interest rate can be partially offset by an increase in household labor supply and a rise in labor income.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.39-46
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• 2011

This study investigates the effects of the DME and n-Butane mixture and of the stratification on combustion characteristics of HCCI engine by chemical reaction calculation. First, the existing DME reaction scheme and n-Butane is combined to make new chemical reaction model, then validating the effectiveness of new scheme. Furthermore, this study verify the HCCI combustion characteristics according to the changes of DME and n-Butane mixture ratio, which shows different auto ignition characteristics. Finally, it confirms the effects of stratification of mixture fuel on the reduction of pressure rise rate.