• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.882-897
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• 1998

This experiment was conducted to predict the effects of motional characteristics on the fertility of Korean native cattle(KNC) by using CASA technology and in vitro fertilization system. Twenty-six KNC frozen semen straws were obtained from Korean KNC improvement department, livestock improvement main division, national livestock cooperatives federation in Korea. Specimens were allowed to thaw at $37^{\circ}C$ for 30 sec in water bath. Semen analysis was performed on semen image analysis system(SIAS, Medical supply, Korea) adjusted to the gate settings and used the semen droplet ($5{\mu}l$) placed on Makler counting chamber(Sefi medical instrument, Israel) prewarmed at $37^{\circ}C$. The same person used the same micropipette to fill the Makler counting chamber. A total of 150 or more of sperms were analysed in each specimen by a single trained person by scanning at least 5 to 10 fields. The oocytes collection, in vitro maturation, IVF, in vitro culture and determination of the cleavage rate were performed by the technique, as described by Hwang et al (1997). Statistical analysis was done by linear regression with use of the Sigma plot program on a IBM personal computer. The cleavage rate in vitro fertilized oocyte was significantly correlated(P<0.05) with MOT, VCL, VSL, VAP, ALH, BCF and MAD, but not CON, LIN, STR, WOB, DNM, DNC and HYP in regressional analysis. The results show that some kinematic characteristics of frozen-thawed semen by CASA can be predict the fertility in in vitro model system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.99-108
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• 1991

Rapid changes of urban hydrologic events need new management operation rule of detention reservoir which is essential outflow control system in urban area. Therefore, this study is to develop the outflow management method of Seoul city considering the Han river flood characteristics, to analyze the inundation of detention reservoir according to variation of design storm patterns, and to examine the safety of gate due to design flood water level. From this study, new operation rule is presented. The design storm patterns are determined by instantaneous intensity method and Huff's quartile method. And the inflow hydrograph of detention reservoir is obtained by applying ILLUDAS model and RRL method. The operation rule of existing drainage pump is designed to have linear relation between storage and pumping discharge. But in this study, it is effective for preventing inundation when the operation rule of drainage pump have Gaussian function which is combined the storage of detention reservoir with its inflow according to increasing or decreasing of inflow hydrograph.

• Journal of Veterinary Clinics
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• v.30 no.1
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• pp.17-21
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• 2013

The objectives in the present study were to evaluate the therapeutic effect of a sodium salts mixture against Salmonella gallinarum infection in broiler. Of this study, sixty broilers at two weeks of age (body weight, $450{\pm}35$ g) were used to estimate the efficacy of a sodium salts mixture (3.25 mg sodium azide, 2.45 mg sodium cyanide, 0.8 g sodium chlorate) against Salmonella gallinarum infection in broiler with drinking water. Broilers challenged with S. gallinarum were administered with ${\times}$ 1(group I) and ${\times}$ 2(group II) sodium salt mixture for seven days, and cecal content samples were collected at the gate of treatment and on 1st, 3rd, 5th, and 7th day after administration. Changes in body weight and cecal shedding of S. gallinarum were monitored during the experimental period. All groups treated with the sodium salt mixture slightly increased body weight compared to control group but there is no significant difference. At 7th day after administration, the number of S. gallinarum in group I and II was significantly decreased compared to control group (p < 0.001). In the hematological and blood biochemical analysis, values of parameters were not significantly different between the treated groups and control group. From results of the present study, the sodium salt mixture had therapeutic effect on S. gallinarum infection in broilers.

• 보존과학연구
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• s.26
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• pp.141-164
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• 2005

Most of the stone cultural properties is exposed to the weathering factor(rain, windetc.), so the shelter is constructed for reduction of its direct effect. But the shelter is indicated some problems that inharmoniousness of the surroundings, in section disturbance for insufficiency of light, the loss about the value of cultural properties and so on. So we have investigated on environmental condition (temperature, relative humidity, wind etc.) at the Standing Stone Buddhist Triad in Bae-ri, Gyeongju and Rock-carved Triad Buddha in Seosan because check the effect of the shelter. As the result, the Standing Stone Buddhist Triad in Bae-ri, Gyeongju is located a pine wood and a lot of bamboo grow naturally in nearing. Environmental difference on inside and outside of the shelter is not found because opened on all sides. But there is so dim for the direction of the sunlight that can't see the Standing Stone Buddhist. The base rock of Rock-carved Triad Buddha in Seosan well develop with crack and break, and the vegetation(trees, moss, lichen etc.) grow naturally in surroundings. Environmental difference on inside and outside of the shelter is found because closed on all sides and opened the front gate only inspection time. Inside of the shelter was too calm(air-velocity not detected) and humid(over 75%RH). Also the surface is occurred the dew(at 2-4 pm) and the efflorescence for effect of the water(rain, dew etc.). Besides the head of the central Buddhist is so dangerous for crack.

• Ocean and Polar Research
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• v.28 no.4
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• pp.369-383
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• 2006

The Saemangeum project is one of the biggest reclamation efforts in Korea and may cause coastal ecosystem change due to altered environments and habitat loss. Since February 2002, benthic environment and community structure in the Saemangeum studied area were studied to assess the influence of the project on macrofaunal community. The result of seasonal study from February, 2002 to August 2005 is reported here. Overall, changes of species numbers and dominant species of benthic animals in the periods before (1988) and after $(2002{\sim}2005)$ the Saemangeum dike construction were not evident both inside and outside the dike. However, local environmental and community change were noted The partial completion of Saemangeum dike $(4^{th}\;dike)$ in June 2003 altered water circulation and sediment deposition patterns both inside and outside the dike. Fine sediment was accumulated inside and outside the $4^{th}$ dike while coarse sediment dominated near the main channel (Sinsi gate). Benthic community resl)ended to the altered sediment type in these areas. Species number and diversity in both site was low compared to other sites. The dominant species in these areas were composed of the benthos that had not commonly occurred in the Saemangeum subtidal area.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.2
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• pp.75-82
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• 2020

The Daehang-ri intertidal flat located the just outside of the Saemangeum dike has been reported to show new-developing flats. Based on the topographic surveys of 21 times from 2000 to 2016 by a leveling method every year, this site clearly shows variation of deposition/erosion in time and space. Deposition has consistently occurred at the rate of +3.75 cm per year at the area along the dike (Zone 1), and this tidal flat is expanding and prograding seaward. In the area of far from the dike (Zone 2), on the other hand, erosion prevails at the rate of -2.38 cm per year, and this zone tends to retreat landward. However, the erosional trend of Zone 2 has slightly slowed down since 2014. As a whole from 2000 to 2016, net deposition is recorded over 3.0 m at the upper beach and the area adjacent to the dike (Zone 1), while erosion up to 1.0 m in Zone 2. In conclusion, the results at the Daehang-ri intertidal flat clearly revealed that its topographic changes were induced by the artificial structures and water masses through its sluice gate. Counter-clockwise gyre newly created after the sea dikes construction probably results in relocating of sediment outside the dike 1 by transportation of materials eroded from the south to the north along the coast.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.277-291
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• 2012

Aquaculture is challenged by a number of constraints with future efforts towards sustainable production. Global climate change has a potential damage to the sustainability by changing environmental surroundings unfavorably. The damaging parameters identified are water temperature, sea level, surface physical energy, precipitation, solar radiation, ocean acidification, and so on. Of them, temperature, mostly temperature elevation, occupies significant concern among marine ecologists and aquaculturists. Ocean acidification particularly draws shellfish aquaculturists' attention as it alters the marine chemistry, shifting the equilibrium towards more dissolved CO2 and hydrogen ions ($H^+$) and thus influencing signaling pathways on shell formation, immune system, and other biological processes. Temperature elevation by climate change is of double-sidedness: it can be an opportunistic parameter besides being a generally known damaging parameter in aquaculture. It can provide better environments for faster and longer growth for aquaculture species. It is also somehow advantageous for alleviation of aquaculture expansion pressure in a given location by opening a gate for new species and aquaculture zone expansion northward in the northern hemisphere, otherwise unavailable due to temperature limit. But in the science of climate change, the ways of influence on aquaculture are complex and ambiguous, and hence are still hard to identify and quantify. At the same time considerable parts of our knowledge on climate change effects on aquaculture are from the estimates from data of fisheries and agriculture. The consequences may be different from what they really are, particularly in the temperature region. In reality, bivalves and tunicates hung or caged in the longline system are often exposed to temperatures higher than those they encounter in nature, locally driving the farmed shellfish into an upper tolerable temperature extreme. We review recent climate change and following environment changes which can be factors or potential factors affecting shellfish aquaculture production in the temperate region.

• Journal of architectural history
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• v.19 no.6
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• pp.7-22
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• 2010

This study includes a review of the relevant literature and data on the Gyeolseong Eupseong, a coastal castle town of the Joseon Period. During the process of building the Gyeolseong Eupseong, Eupchi(administrative office) was transferred to several different locations for the following reasons:. first, to strengthen defensive capabilities by utilizing the locational advantages of the Seokdang Mountain Fortress, second, to secure sufficient space for holding the castle and have access to water in times of emergencies, third, to strengthen coastal defence by utilizing geographical advantages. Most of the Gyeolseong Eupseong was damaged during the Japanese colonial period. At present, there remain only part of the castle's facilities and some facilities that were restored later in modern times; 4 building sites have been identified. Remaining and destructed buildings can be identified through old maps(the local maps of 1872) and Zirizi and Eupzi(geography books). Also identified were 2 castle gate sites where a 1,500m-long stone castle wall and an ongseong(a crescent-shaped defensive structure), 5 chiseongs, and a most were constructed. The Gyeolseong area is assumed to have been a strategic foothold to defend the west coast from the days before the Three Kingdom Period. However it is very difficult to find any records created before the Joseon Period. Therefore, the time of the restoration of the Eupchi should be determined based on records created in the late Joseon Period. Finally, excavation work needs to be done to identify the locations of the castle's facilities.

• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.27-35
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• 2013

One of the most important factors that have a large influence on performance of the solar water heater system is performance of the solar collector, more detailedly, coating technology on the surface of the solar collector, which can provide high solar absorptance and low emittance. The core of the coating technology is to coat solar selective surfaces. In this study, various performance experiments are carried out using $Cr_2(SO_4)_3{\cdot}15H_2O$ coating technology. Here, IGBT(Insulated Gate Bipolar Transistor) of 5000A-15V was used as the surface processing rectifier which can stably output power and also can control voltage and current. The plating solution mainly contains black chrome$^{+3}$ concentration, H-y Conductivity, N-u Complex, NF Additive and NC-2 Wetter. Before applying the black chrome coating on the copper plate, optimal conditions are provided by using various preprocessing methods such as removal of fat, activation, electrolytic polishing, nickel strike, copper sulfate plating and bright neckel plating, and then the automatic continuous coating experiment are performed according to plating time and cathode current density. In the experiment, after the removal of fat, chemical polishing, nickel strike and activation processes as the preprocessing methods, the black chrome coating was performed in a plate solution temperature of $28^{\circ}C$ and a cathode current density of $18A/cm^2$ for 90 seconds. The thickness of chrome and nickel on the coated plate is $0.389{\mu}m$, $159{\mu}m$ respectively. As a result of the coating experiment, it showed the most excellent performance having a high solar absorptance of 98% and a low emittance of $5{\pm}1%$ when the black chrome surface had a thickness of $0.398{\mu}m$.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.323-331
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• 2019

In this study, a computational model approach for the modeling of hydrodynamic pressures acting on radial gates during strong earthquakes is proposed. The use of the dynamic layering method with the Arbitrary Lagrangian Eulerian (ALE) algorithm and the SIMPLE method for simulating free reservoir surface flow in addition to moving boundary interfaces between the fluid domain and a structure due to earthquake excitation are suggested. The verification and validation of the proposed approach are realized by comparisons performed using the renowned formulation derived by the experimental results for vertical and inclined dam surfaces subjected to earthquake excitation. A parameter study for the truncated lengths of the two-dimensional fluid domain demonstrates that twice the water level leads to efficient and converged computational results. Finally, numerical simulations for large radial gates with different curvatures subjected to two strong earthquakes are successfully performed using the suggested computational model.