• Korean Journal of Animal Reproduction
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• v.21 no.1
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• pp.53-59
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• 1997

This study was conducted to investigate the effect of hormones on in vitro maturation of porcine follicular oocytes. The results obtained were as follows : 1. The maturation rates of oocytes cultured in medium containing FSH 1, 10, 50 and 100$\mu\textrm{g}$/ml were 44.6, 58.5, 42.6 and 37.9%, respectively. And those were no difference to maturation rates among the medium containing FSH. However, the maturation rate(13.7%) of oocytes cultured without FSH was significantly(P<0.05) lower than those of oocytes cultured with FSH. 2. The maturation rates of oocytes cultured in medium containing hCG 0, 1, 10, 50 and 100IU/ml were 12.2, 11.9, 17.9, 21.9 and 45.6%, respectively. The maturation rate of oocytes cultured with 100IU/ml hCG was significantly(P<0.05) higher than those of oocytes cultured with 0~50IU/ml hCG concentrations. 3. The maturation rates of oocytes cultured in medium containing E2 0, 1, 10, 50 and 100$\mu\textrm{g}$/ml were 13.7, 10.5, 14.9, 11.4 and 5.9%, respectively. There were no differences to maturation rates among the E2 concentrations. 4. The FSH＋hCG treatment was the highest maturation rate in medium containing different combination of FSH, hCG and E2.

• Korean System Dynamics Review
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• v.13 no.2
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• pp.25-45
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• 2012

The purpose of this study is to estimate the effects of healthy city policies on residents' walking. In order to estimate promotion of walking rates by healthy cities policies, it developed System dynamics(SD)-based model which showed causal relationships among urban design, public health policies, and walking levels. SD technique is useful for future forecast and policy impact assessment. The spatial units of the SD-based system for policy impact assessment included 66 cities, counties, and communities in Seoul Metropolitan Area. The system simulation was planned to be run for 21 years from 2009 to 2030. For this study, 3 alternatives were proposed with combinations of length of bike lanes, number of bus routes, crime rates, self-reported good health status rates, and obesity rates. As a result of simulations, residents' participation rates for walking were increased from 1.00% to 9.98%. This study contributes to better understanding the benefits of healthy cities that are associated with individual walking. It further provided useful insights into planners' role in promoting health. The paper concluded with a discussion on future research opportunities and implications for public policies in urban and transportation and public health.

• Korea journal of population studies
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• v.23 no.1
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• pp.5-29
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• 2000

도시화 및 산업화는 가족의 애정기능 증대, 친족관계 약화, 공사영역분리, 여성의 교육수준 향상 및 취업기회 증가, 부부관계의 평등성 추구 등을 통해 이혼을 증가시키는 요인으로 알려져 왔다. 혼인·이혼신고 자료와 인구주택총조사 자료를 활용하여 1970년∼1995년 동안 발생한 한국의 성별, 연령별, 시도별, 교육수준별 이혼율을 비교하였다. 이혼수준을 측정하기 위하여 조이혼율, 일반이혼율, 연령별이혼율, 연령표준화 이혼을 전체인구와 유배우인구를 대상으로 각각 산출하였고, 각종 이혼력 지표의 특성을 논의하였다. 1970년∼1995년 동안 이혼율이 3배 증가하였으며, 1995년 현재 유배우인구 천 명당 3.2건의 이혼이 발생하였다. 동기간 동안 24세 이하 연령층의 이혼율이 가장 높았고, 전 연령층에 걸쳐 빠른 속도로 이혼율이 증가하였는데, 증년층의 이혼율 증가 속도가 가장 빨랐고, 남성보다는 여성의 상대적 이혼율 증가 정도가 더 빨랐다. 시도별 이혼율은 전연령층에 걸쳐 서울, 부산, 인천, 대전, 경기, 제주도가 높았고, 강원도와 전라북도 25∼34세 연령층의 이혼율이 높았다. 교육수준별 이혼율이 남자는 초등학교 졸업집단에서, 여자는 고등학교 졸업 집단에서 가장 높았고, 남자는 대졸 이상 집단, 여자는 무학 집단에서 가장 낮게 나타났다.

• Nuclear Engineering and Technology
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• v.10 no.2
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• pp.79-86
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• 1978

The object of this study was to obtain data on air-distributions in two-phase up flow in vertical rod-bundle test-section. The test-section in this study was a hexagonal shaped 61-rod bundle where each rod was wrapped with helical spacers. The variables were flow rates of air and water and air inlet positions. Experimental data were obtained at the outlet of the test-section. The experiments were performed in two parts. Firstly, data were taken at increasing flow rates of air keeping water flow rates constant, and secondly, at simultaneous increase of air and water flow rates. At each flow condition, air supply position could be changed to 4 different positions. Data obtained by electrical void-needle technique were analyed and are presented here in graphical forms for comparison. The results of this study demonstrate qualitatively that air-distribution tends to be more uniform as water flow rates are increased. The air supply positions have noticeable effects on the pattern of air-distribution.

• Animal cells and systems
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• v.10 no.4
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• pp.191-196
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• 2006

This study was carried out to evaluate soil carbon cycling of a 36-year-old larch (Larix leptolepis) stand in Korea. The aboveground and soil organic carbon storage, litterfall, and soil respiration rates were measured over twoyear periods. The estimated aboveground biomass carbon storage and increment were 4220 gC $m^{-2}$ and 150 gC $m^{-2}\;yr^{-1}$, respectively. Mean organic carbon inputs by needle and total litterfall were 118 gC $m^{-2}\;yr^{-1}$ and 168 gC $m^{-2}\;yr^{-1}$, respectively. The aboveground carbon increment of the stand was similar to the annual input of carbon from total litterfall. The soil respiration rates correlated exponentially with the soil temperature at a depth of 20 cm ($R^2$ = 0.86). In addition, the exponential regression equation indicated a relatively strong positive relationship between the soil respiration rates and soil temperature, while there was no significant relationship between the soil respiration rates and the soil moisture content. The annual mean and total soil respiration rates were 0.40 g $CO_2\;m^{-2} h^{-1}$ and 3010 g $CO_2\;m^{-2}\;yr^{-1}$ over the two-year study period, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.8 no.2
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• pp.9-17
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• 1986

Effect of nitrogen rate with and without chance of Phosphorus and Potassium rate was investigated in a field experiment. Percentage of plant mortality after transplanting increased with N rates above 32.5kg/10a. The content of total nitrogen increased and postassium decreased slightly as the rates of applied N was increased, but the contents of total alkaloid and phosphorus were not affected at each growing stage. It was considered that the application of 17.5kg of P2O5 and 35.0kg of K2O Per 10a might be sufficient for high yield and good Quality. As the N rates being increased, the yield, value, contents of total alkaloid and total nitrogen of cured leaf increased However, the Brice per kg was not significantly different among 17.5 ~ 37.5kg / 10a of N rates. The application of 37.5kg/10a of N may be profitable for farm economy; but, the N application should be controlled 17.5~22.5kg/10a for the low nitrogen and alkaloid leaf.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.209-216
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• 1998

The purpose of present study is to improve the efficiency of fusion and the developmental rates of nuclear transplanted embryos to produce genetically identical twins from Korean native cattle. The diameter of aspirated follicles had no significant effect on the recovery rates of oocytes collected by ovum pick-up technique. The fusion rates of nuclear transplanted embryos were significantly higher in 50 and $100{\mu}s$ DC duration groups(73.3 and 72.0% ; respectively) than that in $30{\mu}s$ group(55.6% ; p<0.05). The cleavage rates of nuclear transplanted embryos appeared to be significantly higher in donor nuclei derived from in vivo (65.0%) than in those from in vitro (50.5% ; p<0.01), but the developmental rates to morulae and blastocysts were not significantly different between them(13.7 vs 10.9%, respectively).

• Advances in environmental research
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• v.4 no.1
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• pp.17-24
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• 2015

In this study, we numerically investigated the effect of pressure (100-250 bar), temperature (274-288 K), and salinity (3.5% w/w electrolytes) on $CO_2$ hydrate dissolution rates in the ocean. Mass transfer equations and $CO_2$ solubility data were used to estimate the $CO_2$ hydrate dissolution rates. The higher pressure and lower temperature significantly reduced the $CO_2$ hydrate dissolution rates due to the increase of $CO_2$ particle density. In the high salinity condition, the rates of $CO_2$ hydrate dissolution were decreased compared to pure water control. This is due to decrease of $CO_2$ solubility in surrounding water, thus reducing the mass transfer of $CO_2$ from the hydrate particle to $CO_2$ under-saturated water. The results obtained from this study could provide fundamental knowledge to slow down or prevent the $CO_2$ hydrate dissolution for long-term stable $CO_2$ storage in the ocean as a form of $CO_2$ hydrate.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.304-309
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• 2008

The heating and cooling performances of system multi-air conditioner for various refrigerant flow rates with high-head and long-line conditions are experimentally investigated. The maximum head and tube length were 110 m and 1000 m, and the two different adjustments of refrigerant flow rates were +20 % and -20 %, respectively. The experimental system was composed of 4 outdoor units with module systems, and 13 indoor units which were joined with the mode change unit by single-tube circuit. Field tests without indoor and outdoor temperature control were performed in a general office building with two different refrigerant flow rates. Especially, the oil level in the compressor was normally maintained at the safety zone. Experimental results were prepared on the p-h diagram.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.99-104
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• 2007

Tracer gas technique is widely used to measure the ventilation rates and/or ventilation effectiveness of building spaces. However, the conventional method using a single tracer gas can measure only outdoor air change rates in a single zone. This paper deals with the multi-gas tracer technique to measure air exchange rates between rooms. Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Experiments are conducted in a simple two-room model with known airflow rates using tracer gases of SF6 and R134a. The concentration decays of two tracer gases are measured after simultaneous injections in each room. The governing equations are derived from the continuity and the mass balance of each room. The data reduction procedure are developed to obtain the inter-room airflow rates using the governing matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, smoothing, and etc, to improve the estimate and interpretation of the results.