• Plant Resources
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• v.8 no.3
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• pp.281-285
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• 2005

In order to select suitable fertilizer level and sowing rate of Dangyo $^{#8}$(hybrid) rapeseed at the southern area of Korea, two varieties of Naehanyuchae (Normal) and Dangyo $^{#8}$(hybrid) rapeseed currently grown for oil production by two fertilizer level with 10-8-8 kg/10a and 15-8-8 kg/10a and three sowing rate with 500 g/10a, 1,000g/10a and 1,500g/10a with relatively high yield was grown at the same condition yield and yield components were observed. Dangyo $^{#8}$(hybrid) rapeseed was superior to oil-eed rapeseed for yield at the 15-8-8 kg/10a of fertilizer and 1,500 g/10a of sowing rate. Fertilizer level, $N-P_{2}O_5-K_{2}O$ = 15-8-8 kg/10a and sowing rate, 1,500 g/10a showed somewhat higher value in two varieties of Naehanyuchae(Normal) and Dangyo $^{#8}$(hybrid).

• Journal of the Korean Society for Heat Treatment
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• v.18 no.2
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• pp.112-118
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• 2005

Study was focused on the effect of the cooling rate on the embrittlement behavior of Zircaloy-4 cladding simulated Loss Of Coolant Accident (LOCA) environment. Claddings were oxidized at given temperature and given time followed by various water quenching in the range of $0.6^{\circ}C$ and $100^{\circ}C$ per second. Cladding failed after water quenching above the threshold oxidation. Threshold oxidation was decreased as the cooling rate increased, which is due to the matensite structure formed during fast cooling rate.

• Journal of Embryo Transfer
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• v.24 no.1
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• pp.21-27
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• 2009

This study was performed to elucidate the effects of addition of ${\beta}-lactoglobulin$ and bovine serum albumin (BSA) in vitro maturation (IVM) and in vitro culture (IVC) medium on porcine embryo production. The development rate to the 2 cell ($71.4{\sim}75.6%$) and blastocyst stages ($6.8{\sim}13.3%$) with different BSA concentrations in IVM medium were similar among treatment groups. Blastocyst hatching rate was significantly higher in the control group (0.0mg/ml) than in the group of 1.0mg/ml supplement (20.0% vs. 0.0%; p<0.05). The development rate to the 2 cell ($62.0{\sim}70.6%$) and blastocyst stages ($15.4{\sim}38.5%$) with different ${\beta}-lactoglobulin$ concentrations in IVM medium was similar among treatment groups. The development rate to the blastocyst was significantly higher in the group of 1.0mg/ml(15.3%) than in the group of 0.5mg/ml supplement (7.6%, p<0.05). The development rate to the 2 cell and blastocyst stages following the first addition of ${\beta}-lactoglobulin$ in IVM medium was significantly higher in the control group (77.0% and 18.9%) and was $0{\sim}44\;hr$(77.2% and 16.9%) greater than that observed in other treatment groups (p<0.05). The development rate to the 2 cell stage ($68.1{\sim}74.8%$) and blastocyst stages ($9.2{\sim}12.7%$) with different BSA concentrations in IVC medium was similar among treatment groups. However, blastocyst hatching rate was significantly higher in the group of 3.0mg/ml supplement (30.0%) than in the control group (0.0%; p<0.05). The development rate to the 2 cell stage ($72.9{\sim}78.0%$), blastocyst ($7.1{\sim}14.2%$) and hatching stages ($33.3{\sim}38.1%$) were not different. The development rate to the 2 cell stage ($63.6{\sim}72.5%$), blastocyst ($8.4{\sim}16.1%$) and hatching stages ($18.2{\sim}37.5%$) at the different culture periods were similar among treatment groups. This study suggested that if the addition level and periods of ${\beta}-lactoglobulin$ addition are adjusted, it is possible to replace BSA in the in vitro porcine embryo production.

• Journal of Animal Reproduction and Biotechnology
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• v.39 no.1
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• pp.40-47
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• 2024

Background: Sperm quality and the number of sperm introduced into the uterus during artificial insemination (AI) are pivotal factors influencing pregnancy outcomes. However, there have been no reports on the relationship between sperm concentration at AI and sperm quality in Hanwoo cattle. In this study, we examined sperm quality and pregnancy rates after AI using sperm inseminated at different concentrations. Methods: We evaluated the motility, viability, and acrosomal membrane integrity of sperm at different concentrations (10, 15, 18, and 20 million sperm/straw) in 0.5-mL straws. Subsequently, we compared the pregnancy rates after AI with different sperm concentrations. Results: After freeze-thawing, sperm at the assessed concentrations showed similar viability and acrosomal membrane integrity. After AI, cattle in the 10 million group had significantly lower pregnancy rates compared to those in the 18 and 20 million groups. Conversely, there were no statistically significant variances observed between cattle in the 10 and 15 million groups. Conclusions: Sperm at concentrations of 10, 15, 18 and 20 million per straw exhibited comparable motility, viability, and acrosomal membrane integrity. However, a concentration of at least 18 million sperm per straw is required to achieve a consistent rate of pregnancy rate in Hanwoo cattle after AI.

• Environmental and Resource Economics Review
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• v.20 no.4
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• pp.859-882
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• 2011

Since two oil crises in the 1970s, Korea has actively engaged in overseas E&P projects to increase energy diversity as well as its self-development rate of energy resources. Korea's energy self-development rate, an index that indicates the ratio of resources acquired through overseas development compared to direct imports. Currently, Korea is conducting a total of 180 promising overseas oil development projects in 36 countries as of the end of 2010. By now, it has secured a reserve of around 1.63 billion barrels and production of around 176 thousand barrels of oil per day. The self-development rate for oil rose from 2.8% in 2006 to 7.4% in 2010. Not content with these remarkable successes, the korean government is planning to raise its self-development rate in oil to 25% by 2019, by promoting the active participation of Korean companies in overseas oil development projects. This paper is concerned with estimation of the required amount of government subsidies that includes loans and financial support through state-controlled banking institutions in order to reach the target 25% rate by 2019. The estimation results shows that government subsidies of at least 268 million dollars are needed for the current rate of 7.4% in oil. However, the amount sharply increases up to 1.25 billion dollars in 2019 when domestic oil demand rises to 1.02 billion barrels.

• Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.52-57
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• 1999

Air-drived rotating biological contactor (RBC) system, which is effective method in filtering performance, was tested for the nitrification capacity in a recirculating system. At ammonia concentrations between 0.029 and 0.528 mg/l, the effect of ammonia loading rate on ammonia removal rate at three different hydraulic loading rates could be defined by the following first­order regression models: Hydraulic loading rate of $14.8 m^3/m^3/day:\;y=39.2\times+3.4 (r^2=0.9137)$, Hydraulic loading rate of $26.5 m^3/m^3/day: y=53.3\times+4.0 (r^2=0.8686)$, Hydraulic loading rate of $37.3 m^3/m^3/day: y=58.4\times+4.2 (r^2=0.7755)$, where, $\times$ is ammonia loading rate (mg/l), y is ammonia removal rate $(g/m^3/day)$, The equations showed the optimal ammonia removal rate at the hydraulic loading rate of $26.5m^3/m^3/day$. Below the ammonia concentration of 2.72 mg/l, first-order regression models between ammonia loading rate and ammonia removal rate at three different rates of speed are defined as follows: Rotational speed of $0.75 rpm: y=28.5\times+4.7 (r^2=0.9143)$, Rotational speed of $1.0 rpm: y=33.6\times+8.4 (r^2=0.9534)$, Rotational speed of $2.0 rpm: y=28.9\times+3.6 (r^2=0.9488)$, where, x is ammonia loading rate (mg/l), y is ammonia removal rate $(g/m^3day)$. The equations show the ammonia removal rate at the rotational speed of 1.0 rpm is significantly higher than that at the rotational speed of either 0.75 rpm or 2.0 rpm (P<0.05).

• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.11-19
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• 2000

This study aims to examine the characteristics of the water quality variation in relation to the change of water exchange rate with respect to the development phases of the Pusan port. To clarify the characteristics, water exchange caused by the variations of coastline shape and water surface area was examined by the numerical experiments using the Lagrangian particle tracking model based on 2-D shallow water equation. As the results of numerical experiments, it was proved that the water exchange in the Pusan port was decreased mainly due to the port development and the breakwaters construction. During the port development phases from 1875 to 1998, 35% of the sea-space in the port had decreased to make hinterland spaces. This resulted in the loss of wet-land and coastline change as well as decrease of the water exchange rate at the sea side. The city population in that period had rapidly increased from several thousands to 4 millions, resulting in the large discharge of sewages into the port area. Under the these environmental conditions, it can be clearly said that the water quality in the Pusan port is sensitively affected by the discharge of urban sewages decrease of the water exchange rate in relation to port and urban developments. In the study, the temporal changes of water quality were discussed with respect to the port development phases. It was clear that the water quality wad controlled by the exchange rate change under the port development as well as the input impact into the port from the urbanized city area. To make clean sea of the Pusan port, it is suggested that the sewage control, the water exchange and coastline control should be systematically checked under the concept of eco-friendly development and environmental management.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.381.2-381.2
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• 2014

In this study the amorphous carbon films were deposited by PECVD at the substrate temperature range of 250 to $600^{\circ}C$, and the process conditions of higher and lower precursor flow rate, respectively. The temperature was a main parameter to control the density and mirco-structures of carbon films, and their's properties depended with the process temperatrue are changed by controlling precursor flow rate. The precursor feeding rate affect on the plasma ion density and a deposition reactivity. This change of film properties was obtained the instrinsic stress, FT-IR & Raman analysis, refractive index (RI) and ext. coef. (k) measured by ellipsometer. In the process conditions of lower and higher flow rate of precursor it had a different intrinsic stress as a function of the substrate temperature.

• Korean Journal of Veterinary Service
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• v.29 no.1
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• pp.65-70
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• 2006

In order to detection of the intestinal parasites, fecal samples were taken from broiler (n=290), parent stock (n=168) and laying hen (n=114) in Jeonbuk province. The prevalence and identification of intestinal parasites were determined by the fecal examination using the floatation method and microscopical examination, respectively. The detection rate of parasite-eggs from 3 flocks (total=572) was 44.9%. In the breed and type of breeding, infection rate of parasite-eggs was detected 65.5% as broiler (floor breeding, 290 chickens), 20.2% as parent stock (floor breeding, 168 chickens) and 28.9% as laying hen (cage breeding, 114 chickens), in order. In the concern of mixed infection such as single and double, the rate were 40.7% and 4.2%, respectively. Six kinds of infective eggs were isolated 257 fecal sample from 3 flock. They were classified 74.7% as Eimeria spp, 18.1% as Ascaridia galli and 6.0% as Capillaria spp and 0.4% as Heteratkis gallinarum, Railleina spp or Trichostrongylus spp, single or in combination.

• KIEAE Journal
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• v.6 no.3
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• pp.27-34
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• 2006

The recent emphasis on ecological urban development has led to the need to maintain a hydrologic cycle in urban areas. As such, this study proposes decentralized rainwater management, a concept of onsite rainwater management that involves the utilization, infiltration, detention, and retention of rainwater. The main objective of this research is to estimate the proportion of decentralized rainwater management that is needed. From the research that was conducted in this study, it was found that the total runoff quantity increases by 10-20% after district lands are developed, when the probable rate of precipitation every 10 years is within this range. Thus, the runoff rate can be reduced by 10~20% of the total runoff quantity through decentralization. On the other hand, in the scale of housing complex development, the total runoff quantity increases by as much as 10~40% due to the changes in the rate of the impervious surface area. If 10-40% of the total runoff quantity was processed through decentralized rainwater management, the rate of infiltration, detention, retention, and runoff in precipitation prior to development could be recovered.