• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.288-297
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• 1990

The method of analyzing flexible mechanisms with clearances was studied considering flexibility of beams in the mechanism using finite elements. Both ends of a beam were modeled as free following Dubowsky's impact pair model. Instead some force constraints were imposed at imposed at the connections between adjoining links. Coulomb model has been developed using dry frictions in place of tangential damping forces in the impact pair model and the contact compliance and damping coefficient approximated in a form of root function were used. As examples, impacts of a rigid ball in a cylinder, impact beam model and four-bar mechanisms made up of three flexible links with clearance connections were simulated numerically. The results from examples showed similar but a little bit smaller magnitude of impact forces compared with published studies.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.165-175
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• 2017

To minimize the damage caused by summer season such as high temperature and red tide, this study was conducted to investigate the effect of feeding and starvation on the survival rate, growth, growth restoration and physiological response of red seabream Pagrus major which were reared in marine net cage ($6m{\times}6m{\times}6m$). The feeding group was fed throughout the experiment for 10 weeks, whereas starvation group was not fed for 6 weeks and subsequent refeeding for 4 weeks. Survival rates of feeding and starvation groups were 94.4% and 98.1% respectively. The growth rate of starvation group was significantly lower than feeding group during starvation period, but recovered rapidly after feeding. The nutritional status such as albumin, total protein, total cholesterol, triglyceride also showed similar tendency to the growth data. Hematocrit and hemoglobin levels were higher in the feeding group than the starvation group during starvation period. Aspartate aminotransferase, glucose and total cholesterol were rapidly increased at the same time (in 5 week) in feeding group, whereas starvation group did not significant difference during starvation period. It was shown that the feeding group is more sensitive to stress than the starvation group. Thus, starvation can be applied as a rearing management plan of net cage fish farm in summer season.

• Korean Journal of Poultry Science
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• v.15 no.4
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• pp.281-286
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• 1988

This experiment was conducted to determine the optimum level of Red Pepper (including seeds) for laying-hen'diet in summer. A total 240 birds of 37 week-old Manina Brown Hen was alloted to 4 treatments, 3 replications per treatment, according to complecately randomized design to find out the effects of adding levels (0, 0.03, 0.05, 0.08%) of Red Pepper on laying Performance and e99 Quality of experimental birds for 10 weeks. The results obtained from this study were summaried as follows : 1) I班 shell thickness was different significantly among treatments, (P＜0.05). Especially, Ta was highest one. 2) Egg shell breaking strength was highly significant difference between C and $T_1$, $T_2$, $T_3$ (p＜0.01). 3) Yolk color of $T_1$, $T_2$, $T_3$ was higher than C (p＜0.01), but there was no significant difference between treatments. 4) Egg Production was slightly higher with adding Red Pepper, but the differences were no significant. 5) No significant differences were found in average egg weight among treatments.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.156-160
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• 2010

This study was performed to provide useful information for kentucky bluegrass management during summer by application of plant growth regulator, Trinexapac-ethyl. Visual quality, shoot density and chlorophyll contents of treatment blocks were significantly different from those of control during summer by application of Trinexapac-ethyl. The turfgrass density of treatment was increased of 4ea/$10\;cm^2$, especially about 5ea/$10\;cm^2$ during the growth retarded period of June and July. Chlorophyll contents index and visual quality of kentucky bluegrass were improved by application of Trinexapac-ethyl during summer, too. In addition, the occurrence of foliage in rainy and high temperature season was less than that of control. However, there was no significant difference in the root length of Kentucky Bluegrass. Meanwhiles, mowing height of kentucky Bluegrass was suppressed by 38% at 2 WAT week after treatment and that there was no significant growth of treatment at 4 WAT. In this experiment, turfgrass quality was significantly better than that of control during July, even though trinexapac-ethyl wasn't applied at all in July. Consequently, periodic treatment of trinexapac- ethyl from spring would be very important to promote the turfgrass visual quality during summer which is unfavorable season on the growth of kentucky bluegrass. And it is possible to reduce mowing times at least 30% for 2 weeks by one application of Trinexapac-ethyl 0.02~0.03 ml/$m^2$ in kentucky bluegrass fairway. Additively, trinexapac- ethyl treatment can be helpful environmentally by cutting down the fertilizers and pesticides in golf course.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.53-59
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• 2005

Influenza is an important public health problem which occurs almost every winter in temperate climates and is often associated with increased rates of hospitalization and death. In 1999, our influenza surveillance was initiated with 4 voluntary sentinel physicians and the Public Health Center. During the 2003-2004 influenza season, 124 influenza viruses were isolated from 401 clinical specimens, which were collected from patients with Influenza-like illness(ILI) in Seoul. The case definition of ILI is a case with fever more than $38^{\circ}C$ and systemic symptoms; cough, or sore throat. ILI was the highest at the 20-49 age $group(23\%)$ and the rate of virus isolation was the highest at the 7-19 age $group(50\%)$. Among 124 influenza viruses, isolates 83 were identified as A/H3N2 type and others were subtyped as influenza B viruses in 2003-2004 season. Influenza viruses were collected $39.1\%$ at Nowon-Gu, $13.5\%$ Gangnam-Gu and Seocho-Gu etc. and the isolate rate of virus had the area difference; Yongsan-Gu $66.7\%$, Gangnam-gu $50.0\%$, Nowon-Gu $39.9\%$, Kangbuk-Gu $36.8\%$, Seocho-Gu $27.8\%$, Dongjak-Gu $21.2\%$. Out of 401 individuals, 160 was vaccinated $(40\%)$ and the vaccination rate was the highest at the 20-49 age $group(32\%)$. These findings may contribute to the recommondation of the influenza vaccine formulation and the development of influenza control measure.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.133-140
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• 2008

The growth of root and shoot normally decline dramatically in mid-summer of Korea, moreover the cool-season turfgrassgrass eventually wither to death over $30^{\circ}C$. The increase of air temperature also drives the heat of soil, that makes stress on root system. The heat stress affects physiological mechanisms of hormonal unbalance that stimulates shoot growth, photosynthesis, and transpiration. To solve those problems, many studies have been carried out to control soil moisture and OM content to decrease soil temperature for dissolving the growth retardant by heat stress. This study initiated to analyze the change of soil temperature with soil moisture, and the effect of soil depth and moisture content on heat transmit and thermal changes on turfgrass growth(productivity, green color, and damage by dryness and high temperature). Kentucky bluegrass plots prepared with 25%, 33%, 40% soil moisture treatments. Soil temperature was measured every five min. with four thermo-sensors at 12 and 2 cm soil depth. The most acceptable growth showed at 33% soil moisture, but the worst result showed at 40%. The soil moisture seriously affected on the growth of Kentucky bluegrass, however the quality of turfgrass may acceptable if we can control soil moisture down to 33% when the flooding season of monsoon.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.100-108
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• 2012

The purpose of the study was to evaluate the influence of shading and ventilation on Mean Radiant Temperature(MRT) of the outdoor space at a summer outdoor. The Wind Speed(WS), Air Temperature(AT) and Globe Temperature(GT) were recorded every minute from $1^{st}$ of May to the $30^{th}$ of September 2011 at a height of 1.2m above in four experimental plots with different shading and ventilating conditions, with a measuring system consisting of a vane type anemometer(Barini Design's BDTH), Resistance Temperature Detector(RTD, Pt-100), standard black globe(${\O}$ 150mm) and data acquisition systems(National Instrument's Labview and Compfile Techs' Moacon). To implement four different ventilating and shading conditions, three hexahedral steel frames, and one natural plot were established in the open grass field. Two of the steel frames had a dimension of $3m(W){\times}3m(L){\times}1.5m(H)$ and every vertical side covered with transparent polyethylene film to prevent lateral ventilation(Ventilation Blocking Plot: VP), and an additional shading curtain was applied on the top side of a frame(Shading and Ventilation Blocking Plot: SVP). The third was $1.5m(W){\times}1.5m(L){\times}1.5m(H)$, only the top side of which was covered by the shading curtain without the lateral film(Shading Plot: SP). The last plot was natural condition without any kind of shading and wind blocking material(Natural Open Plot: NP). Based on the 13,262 records of 44 sunny days, the time serial difference of AT and GT for 24 hour were analyzed and compared, and statistical analysis was done based on the 7,172 records of daytime period from 7 A.M. to 8 P.M., while the relation between the MRT and solar radiation and wind speed was analyzed based on the records of the hottest period from 11 A.M. to 4 P.M.. The major findings were as follows: 1. The peak AT was $40.8^{\circ}C$ at VP and $35.6^{\circ}C$ at SP showing the difference about $5^{\circ}C$, but the difference of average AT was very small within${\pm}1^{\circ}C$. 2. The difference of the peak GT was $12^{\circ}C$ showing $52.5^{\circ}C$ at VP and $40.6^{\circ}C$ at SP, while the gap of average GT between the two plots was $6^{\circ}C$. Comparing all four plots including NP and SVP, it can be said that the shading decrease $6^{\circ}C$ GT while the wind blocking increase $3^{\circ}C$ GT. 3. According to the calculated MRT, the shading has a cooling effect in reducing a maximum of $13^{\circ}C$ and average $9^{\circ}C$ MRT, while the wind blocking has heating effect of increasing average $3^{\circ}C$ MRT. In other words, the MRT of the shaded area with natural ventilation could be cooler than the wind blocking the sunny site to about $16^{\circ}C$ MRT maximum. 4. The regression and correlation tests showed that the shading is more important than the ventilation in reducing the MRT, while both of them do an important role in improving the outdoor thermal comfort. In summary, the results of this study showed that the shade is the first and the ventilation is the second important factor in terms of improving outdoor thermal comfort in summer daylight hours. Therefore, it can be apparently said that the more shade by the forest, shading trees etc., the more effective in conditioning the microclimate of an outdoor space reducing the useless or even harmful heat energy for human activities. Furthermore, the delicately designed wind corridor or outdoor ventilation system can improve even the thermal environment of urban area.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.386-396
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• 2018

Cropland is sources of atmospheric nitrous oxide ($N_2O$) and carbon dioxide ($CO_2$). However, the contribution of the fallow season to emission of these gases has rarely been determined. In this study, a field experiment encompassing three treatments was conducted to determine efflux of $N_2O$ and $CO_2$ in cropland during fallow season. The treatments were hairy vetch (H.V.), rye and control (Con.). The H.V. and rye were sown in middle October and early November, respectively. The soil $N_2O$ efflux among all three treatments in the fallow season (November-April) were $0.014-2.956mg\;N_2O\;m^{-2}{\cdot}d^{-1}$. The cumulative $N_2O$ emissions were $104.4mg\;N_2O\;m^{-2}$ for Con., $85.8mg\;N_2O\;m^{-2}$ for H.V. and $85.0mg\;N_2O\;m^{-2}$ for Rye during the fallow season. The highest $N_2O$ emissions occurred in Con., while H.V. and Rye emissions were similar. Cumulative $CO_2$ emissions were $293.1g\;CO_2\;m^{-2}$ for Con., $242.2g\;CO_2\;m^{-2}$ for H.V., $275.2g\;CO_2\;m^{-2}$ for Rye during fallow season. This study showed that soil $N_2O$ and $CO_2$ average daily emission during fallow season were 28.3% and 27.4%, respectively of the growing season. Our results indicate that $CO_2$ and $N_2O$ emissions from agricultural systems continue throughout the fallow season.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.05a
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• pp.27-35
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• 2003

(시험 1) 육용종계 산란기의 단백질공급수준에 관한 연구: 육용종계 산란기의 적정 단백질공급수중을 구명하기 위하여 강원도 홍천군 북방면소재 홍천종계에서 케이지 사양형태의 아바에이카 육용종계 400수를 공시하여 2001년 2월부터 2001년 12월까지 40주간 (24∼64주령) 1일1수당 단백질 공급량을 18, 20, 22, 24g으로 달리하는 4개처리로 사양시험을 실시한 결과를 요약하면 다음과 같다. 1) 총 산란율과 종란 산란율은 모두 처리간에 유의적인 차이가 있었으며 (P<0.05), 20g 공급구가 가장 높았으나 18∼22g 공급구간에는 유의차가 없어고 24g 공급구는 20g 공급구에 비해 유의적으로 낮았다(P<0.05). 2) 평균난중은 1일 단백질공급수준이 증가할수록 증가하는 경향이었으나 (P<0.05), 20∼24g 공급구간에는 유의차가 없었고 18g 공급구만 24g 공급구와 유의적인 차이가 있었다. 성계생존율은 처리간에 유의적인 차이가 없었다. 3) 계란kg당 또는 계란1개당 사료요구율과 ME요구량은 모두 1일 CP 20g 공급구가 가장 우수했으며(P<0.05), 계란 kg당 사료요구율과 ME요구량에서는 CP 18g 공급구계란1개당 사료요구율과 ME요구량에서는 CP 24g 공급구만 CP 20g공급구오 유의차를 보였다(P<0.05). 4) 계란kg당 또는 계란 1개당 CP요구량은 모두 1일 단백질 공급량이 많아질수록 증가하였으나(P<0.05), 18g과 20g 공급구간에는 유의차가 없었다. 5) 계란kg당 또는 계란 1개당 사료비는 모두 CP 20g 공급구가 가장 우수하였으나(P<0.05), 계란1개당 사료비에서는 18∼20g 공급구간에 유의차가 없었다. (시험 2) 육용종계 하절기 산란피크계의 에너지 공급수준에 관한 연구: 육용종계 산란기의 적정 에너지공급체계를 구명하기 위하여 강원도 홍천군 북방면소재 홍천종계에서 케이지 사양형태의 로스 육용종계 400수를 공시하여 2002년 4월부터 2003년 1월까지 40주간 (24∼64주령) 표2와 같은 4가지 에너지공급체계로 사양시험을 실시한 결과를 요약하면 다음과 같다. 1) 총 산란율, 종란 산란율, 평균난중 및 성계 생존율은 모두 처리간에 유의적인 차이가 인정되지 않았으나, 산란율은 1일 에너지공급량이 많을수록 오히려 저하하는 경향을 보였다. 2) 사료요구율, ME 및 CP요구량과 사료비는 모두 1일 에너지공급량이 많아질수록 증가하는 경향을 보였다(P<0.05).

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.245-248
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• 2004

The prediction of the strength of cold weather concrete and the analysis of the insulating material effect were performed to apply the prediction function with maturity concept for quality control of them in this study. The several results driven from above processes were summarized as followings. First, the difference between the temperature of cylinder covered with insulating materials and that of cylinder without them was $4.5\~6.0^{\circ}C$. Second, the maturity of concrete was suggested to be keep higher than $96\~115^{\circ}C{\cdot}D$ until at least 7-day and the temperature of fresh concrete was suggested to be keep above $10^{\circ}C$ directly after set.