• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.12
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• pp.1301-1309
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• 2008

The curved portion fur each section running safety evaluation interpretation according to the track condition for improving the curved portion passage rate of a vehicle by using the multibody analysis model of the Saemaeul train was carried out. As a result, The excess of cant reaches the bad effect to the running safety in case the radius of curvature is small. In case the radius of curvature was large, we could confirm that the deficiency of cant reached the bad effect to the running safety. In the curved portion, the circular curve section most badly showed the running safety. The deficiency of curve length reaches the bad to the running safety. In the curved portion, the circular curve section most badly showed the running safety. Therefore the track condition(cant, transition curve length, etc) can reach the bad effect to the running safety of a vehicle, the exact design is required.

• Journal of Embryo Transfer
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• v.33 no.3
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• pp.169-175
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• 2018

It has been claimed that artificial insemination (AI) of cows with frozen-thawed semen treated with commercially produced kits, Wholemom (in favour of female gender) increases the birth chance of calves with desired sex ratio by approximately 85% without decrease of pregnancy rates. Hence, this study was conducted to investigate the efficacy of wholemom kits as combined with frozen-thawed bovine semen during in vitro fertilization on the in vitro fertilization and developmental efficiency and sex ratios such as some reproductive parameters in bovine. For this, 1,737 oocytes were in vitro fertilized and developed. Agglutination effects on bovine after treatment of Wholemom kit were observed by time passage and dose respectively. To determine sex of embryos, Bovine embryo Y-specific gene primers(ConEY) and Bovine specific universal primer(ConBV) were used as multiple PCR method. Fertilization rate of wholemom-treated group was significantly lower than its of control group[66.9% (1,156/1,737) in Wholemom-treated group; 75.0% (610/813) in control group]. However, developmental rate after fertilization of both wholemom-treated and control groups were not significantly different [26.1% (404/1,156) in Wholemom-treated group; 27.4% (224/610) in control group]. Sex ratio of in vitro fertilized embryo with frozen-thawed semen treated with wholemom kit was determined by multi PCR. Female ratio in wholemom-treated group [85.4% (173/201)] was significantly higher than its of control group [47.2% (66/141)]. In conclusion, wholemom treatments of semen used in the in vitro fertilization and development of bovine oocytes provided increase in female ratio with decrease of fertilization rate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.10
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• pp.907-913
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• 2005

The present study has been conducted to investigate convective heat/mass transfer in the cooling passage with bleed holes. The rotating square channel has 40.0 mm hydraulic diameter and the bleed holes on the leading surface of the channel. The hole diameter of bleed hole is 4.5mm and its spacing is ( p/d:4.9) about five times of hole diameter. Exit mass flow rate through bleed holes is $0\%,\;10\%\;and\;20\%$ of the main mass flow rate respectively. rotation number is fixed 0.2. A naphthalene sublimation technique is employed to determine the detailed local heat transfer coefficients using the heat and mass transfer analogy. The cooling performance is influenced by exit mass flow rate through bleed holes and Coriolis force of rotating channel for fixed Reynolds number. The heat transfer on the leading surface is decreased due to Coriolis force. However the total heat transfer is enhanced around holes on the leading surface because of trapping flow by bleeding.

• Korean Journal of Microbiology
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• v.3 no.1
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• pp.1-6
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• 1965

Over a period of 1962-64, a transmission-experiment of witchess' broom of jujube tree by stem-grafting was conducted. When stem-grafting of sound scions upon diseased roots or diseased scions upon sound roots were carried out, disease transmission of high rate was witnessed; 99% in the former and, in the latter, 62% of the stocks which saw union by callussing and had new shoots. Even when the diseased scions by stem-grafting or the diseased buds by budding upon sound stock died away, the transmission rate was 21% in stem-grafting and 14% in budding which seems to show that, when tissues of diseased plants and stocks are kept contacted over a certain period, the disease transmission occurs. And when the recovered scions taken from once diseased tree were grafted upon diseased roots, the transmission rate was 100 % and therefore it is presumed that the immunity could not be acquired even under the assumption of complete recovery from the disease. In stem-grafting of the diseased scions upon sound roots, 98% of the scions which were stored in the cellar, overwintered and grafted in spring was diseased, whereas the disease rate of the scions which were cut and grafted in spring was only 33%. It was particularly noteworthy that 90% of the scions in the former case and only 3% in the latter case were diseased as of June 18th approximately 2 months after the actual grafting and then the latter advanced to 33% with the passage of time. It appears that the pathogen in branches and shoots of the diseased trees standing outdoors become inactivated or diminished during winter. Through its symptom, pathological change in tissue, and easy transmission of the disease via stem-grafting, it seems certain that the pathogen of the witches broom disease in jujube tree is a virus.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1018-1033
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• 2021

In this study, we aimed to assess the effect of flaking on the nutrient digestibility of corn grain in ruminants. In this regard, in vitro rumen fermentation, in situ rumen degradability, and in vivo metabolic experiments were performed. The automated gas production technique was used for the in vitro fermentation experiments. Six types of corn flakes with various degrees of gelatinization (32%, 41%, 48%, 66%, 86%, and 89%) were ground and incubated in rumen fluid to measure rumen fermentation characteristics and digestion rate. The in situ degradability of ground corn, whole corn, and corn flakes with 62% and 66% gelatinization was measured by incubation in the rumen of two cannulated Holstein cows. In vivo metabolic experiments were performed using 12 crossbred goats (29.8 ± 4.37 kg) using a 3 × 3 Latin square design. The dietary treatments consisted of ground corn and flaked corn with 48% or 62% gelatinization. In vitro experiments showed that as the degree of gelatinization increased, the digestion rate increased linearly, while the discrete lag time decreased linearly (p < 0.05). The effective rumen dry matter degradability, determined by in situ fermentation, was 37%p lower in corn flakes than ground corn, assuming a passage rate of 6%/h (p < 0.01), and there was no difference between the two flakes. In the in vivo experiment, there was no difference in dry matter intake, average daily gain, feed efficiency, and nitrogen utilization among the treatment groups (p > 0.05); however, the crude fat digestibility was lower for corn flakes than for ground corn (p < 0.05). To summarize, the rate of fermentation of corn flakes increased as the degree of gelatinization increased. However, non-ground corn flakes had lower rumen digestibility and did not improve in vivo apparent nutrient digestibility, compared with ground corn. In contrast to the assumption that flaked corn provides more energy to ruminant animals than ground corn, we conclude that the digestibility and energy value of corn flakes are lower than those of ground corn if mastication does not sufficiently reduce the particle size of corn flakes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.2
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• pp.74-83
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• 2001

The purpose of this study was investigate to the influence of forest roads characteristics and environment factors on the soil erosion, stability and vegetation survival of cut slope in forest roads. The results obtained could be summarized as follows; 1. The correlated factors between slope erosion and variables in cut slope were altitude, convex, degree of slope, length of slope and soil depth. In the stepwise regression analysis, length of slope and soil hardness was a high significant and its regression equation was given by -89.6136 + 15.0667X14 + 16.6713X15($R^2$ = 0.6712). 2. The main factors influencing the stability of cut slope were significant in order of coverage, middle, convex, length of slope and north, and its discriminant equation was given by -1.019 + 0.064X22 - 0.808X8 - 0.622X24 + 0.742X11 - 0.172X14 - 0.545X6 ($R^2$ = 0.793). 3. The centroids value of discriminant function in the stability and unstability estimated to 1.244 and -1.348, respectively. The boundary value between two groups related to slope stability was -0.1038. The prediction rate of discriminant function for stability evaluation of was as high as 91.3%. 4. The dominant species of invasion vegetation on the cut slope consist with Carex humilis, Agropyron tsukushiense var. transiens, Calamagrostis arundinacea, Miscanthus sinensis var. purpurascens, and Ixeris dentata in survey area. The rate of vegetation invasion more increased by time passed. 5. The life form of invasion vegetation in cut slop showed to $H-D_1-R_{2,3}-e$ type of the hemicryptophyte of dormancy form, dissem inated widely by wind and water of dissminule type, moderate extent and narrowest extent of radicoid type, erect form of growth form. 6. The correlated factors between forest enviroment and coverage appeared north, passage years and middle position of slope at 5% level. The forest environment factors influencing the invasion plants in survey area were shown in order to altitude, passage years, rock(none), forest type(mixed) and stone amount. The regression equation was given by 17.5228 - 0.0911X3 + 3.6189X28 15.8493X22 19.8544X25 + 0.3558X26 ($R^2$ = 0.4026).

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.711-717
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• 2007

In this study, two cell types from porcine females, namely fetal fibroblasts (pFFs) and adult ear fibroblasts (pAEFs) and two passages (3-4 and 7-8) were investigated by evaluating the development rate, blastocyst cell number and the incidence of apoptosis. No significant differences were observed in the cleavage rates of cloned and IVF embryos. The blastocyst rates between the embryos cloned with pFFs ($15.1{\pm}3.2$) and pAEFs ($10.4{\pm}2.6$) did not differ significantly but was significantly (p<0.05) lower in pAEFs than that in IVF ($22.5{\pm}4.5$) embryos. Total cell number in pFFs ($28.4{\pm}4.3$) and pAEFs cloned blastocysts ($24.2{\pm}5.1$) was significantly (p<0.05) lesser than IVF control ($35.4{\pm}3.2$). Apoptosis rates between cloned blastocysts differed significantly (p<0.05) and were significantly (p<0.05) higher than IVF embryos. The blastocyst rates between the cloned embryos cloned with different cell passages did not differ significantly but in embryos cloned with 7-8 cell passage was significantly (p<0.05) lower than the IVF control. Apoptosis signals were detected in IVF and cloned embryos as early as day 3 and the rates of apoptosis increased concurrently with the embryo development. In conclusion, high apoptosis during in vitro preimplantation development resulted in low development rate and total cell number of cloned embryos. Moreover, based on the apoptotic incidence in cloned blastocysts, fetal fibroblasts are more suitable for production of cloned embryos in porcine.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.2
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• pp.103-108
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• 2012

A MILD (Moderate and Intense Low oxygen Dilution) combustor decreases NOx formation effectively during the combustion process and NOx formation is affected significantly by the exhaust gas entrainment rate toward fuel and air. The present study focused on the new MILD combustor, which has coaxial cylindrical tube. The outside tube of the new MILD combustor corresponds to the exhaust gas passage and the inner side tube is the furnace passage. The connection pipe is set between the outer side and the inner side tubes and coaxial air nozzle is inserted at the center of the connection pipe. A numerical analysis is accomplished to elucidate the characteristics of exhaust gas entrainment toward the inner furnace with the changes of air nozzle exit velocity, nozzle diameter, nozzle exit position and exhaust gas side pressure. The entrainment rate is proportional to the square root of air nozzle exit velocity and negatively proportional to the pressure difference between the exhaust gas side and furnace side pressures. The effect of air nozzle exit position is not considerable on the exhaust gas entrainment.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.413-416
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• 2008

The concrete used most in construction materials. There is an overcrowded iron dimensions use of the concrete at time of the other concrete theory on the reinforcing rod back which did congestion and compares it with this, and there are more few dimensions of the aggregate than concrete, and quantity of aggregate passage is superior in mortar than concrete. If a volume rate of the aggregate writes mortar than concrete against this, therefore, unit amount increases, and quantity of paste increases and quantity of dry shrinkage than increase concrete. However, I let I regulate lay priest distribution of the aggregate, and the results rates increase and reduce unit amount and decrease quantity of dry shrinkage, and separation resistance and the gap passage characteristics are judged because it can be it in a substitute document of very superior concrete. I came to carry out the study that I watched to let I was useful a little more and do the improvement repair of a become building wall body, a basement pillar and repair reinforcement of the assistant in the reinforcing rod back, the old age when I made congestion here. I regulated lay priest distribution of the aggregate in the study and regulated substitution rate of the aggregate (40%, 50%, 60%) and divided W/C 30%, 40% standards and produced mortar and I compared quantity of air by this, slump, compression robbery and showed it this time.

• Journal of computational fluids engineering
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• v.19 no.4
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• pp.86-93
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• 2014

Increased demand of power-transformer's capacity inevitably results in an excessive temperature rise of transformer components, which in turn requires improved radiator design. In this paper, numerical simulation of the cooling performance of an ONAN-type (Oil Natural Air Natural) radiator surrounded by air was performed by using CFX. The natural convection of the air was treated with the full-model. The present parametric study considers variation of important variables that are expected to affect the cooling performance. We changed the pattern and cross-sectional area of flow passages, the fin interval, the flow rate of oil and shape of flow passages. Results show that the area of flow passage, the fin interval, the flow rate of oil and shape of flow passages considerably affect the cooling performance whereas the pattern of flow passages is not so much influential. We also found that for the case of the fin interval smaller than the basic design, the temperature drop decreases while a larger interval gives almost unchanged temperature drop, indicating that the basic design is optimal. Further, as the flow rate of oil increases, the temperature drop slowly decreases as expected. On the other hand, when the shape of flow passages are changed, temperature drop is increased, indicating that the cooling performance is enhanced thereupon.