• 한국작물학회지
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• 제27권4호
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• pp.291-295
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• 1982

The biosphere of the earth is not only about to overpass the limit to meet the food demand of the world but also the stability of its food production has been also jeopardized by the disasters and pests, especially by the unpredictable weather disasters. In addition the agricultural and industrial pollution against biosphere aggravates the unstability of agricultural production and constitutes a threat in securing the food of the world. In Korea the yield level of crops has been greatly enhanced by the improved agrotechnologies and varietal improvement, but the yield variability due to unfavorable weather events and pests remained unchanged with the change in time. Among weather-related disasters the drought and flood damages has occurred most frequently and impacted most greatly on the agricultural production and its stability. During last decade (1970-l980) the rice production experienced the average annual loss of 0.544 million metric ton which was composed of 0.21 million M/T by climatic disaster, 0.21 million M/T by disease and 0.12 million M/T by insects, and the annual loss of upland crop production from climatic disasters amounted to 0.06 million metric tons. Especially in 1980, the global climatic disasters due to cold or hot temperature endangered the agricultural production all over the world and also the rice production of Korea recorded the unprecedented yield reduction of about 30 percent due to cool summer weather. Nowadays, the unusual weather conditions are prevaling throughout the world, and agro-meteologists predict that the unpredictable cool summer and drought will often attack the rice and other crops in 1980's. To meet the coming weather unstability and to secure the stable crop production, multilateral efforts should be rendered. Therefore, the Korea Society of Crop Science, which commemorates the 20th anniversary of its founding, prepared the symposium on Meteological Stress in Crop Production and its Countermeasures to discuss the decrease in agricultural production due to weather-related disasters and to devise the multilateral counter-measures against the unfavorable weather events.

• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1142-1151
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• 1999

Today, laboratory animal production has decreased world-wide to half the number estimated in 1970 of more than 100 Mio. This is due to the cell-biological assays which replaced animal experimentation as a first allround method to solve biomedical problems. Animal experimentation remains the most significant experimental method for the study of higher organized physiological systems and their multifactorial connections. This requires maximal uniformity of all quantitative traits among the animals used for such studies (mainly mice and rats) and stability of these traits for reproducing such studies at any time world-wide. The success of the developed methods for the standardization of laboratory animals was analyzed and were found only partly be acceptable. Getting a higher degree of uniformity among standardized inbred animals is blocked by "intangible variance". This is caused by influences of ooplasm, shown by experimental twin and clone studies. Manipulation of this component of variance is essential in the future. - Genetic drifts impair the necessary stability of biological traits. There are a few disadvantages associated with the cryopreservation of embryos and other methods are required. - Dogs and cats were replaced by pigs as laboratory animals. A new line of animal production will evolve over the next 25 years with similarities to the present laboratory animal production, because in future pigs were used as donors for xenotransplants for men.

• 한국기계가공학회지
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• 제13권4호
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• pp.99-105
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• 2014

The domestic airline industry undertakes the production of finished products by assembling existing self-described components via a design process which involves assembly and production steps, after which many of the finished products are exported. However, high reliability and stability must be guaranteed, because customers require high-precision components at the time of manufacturing. In the aircraft parts industry, the mass production of high-value-added parts is limited. Therefore, a small production scale depending on the part is used, as many types of conventional CNC lathe machines with X-axis and Z-axis as well as Z-axis and C-axis CNC milling are used. The parts also rely on high-pressure air to increase production. The most important factors are good stability during processing, as high-precision parts are required, as noted above. It was found that as the C-axis rotation speed increased, the diameter of the cutting tool decreased with a decrease in the surface roughness, while the workpiece rotation speed increased with an increase in the surface roughness.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1486-1493
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• 2012

In this study, we investigated whether galactooligosaccharide (GOS) can be stably and steadily synthesized using immobilized ${\beta}$-galactosidase (${\beta}$-gal) inclusion body (IB)-containing E. coli cells during long-term repeated-batch operation. To improve the operational stability of this enzyme reactor system, immobilized E. coli cells were crosslinked with glutaraldehyde (GA) after immobilization of the E. coli. When we treated with 2% GA for E. coli crosslinking, GOS production continued to an elapsed time of 576 h, in which seven batch runs were operated consecutively. GOS production ranged from 51.6 to 78.5 g/l ($71.2{\pm}10.5$ g/l, n = 7) during those batch operations. In contrast, when we crosslinked E. coli with 4% GA, GOS production ranged from 31.5 to 64.0 g/l ($52.3{\pm}10.8$, n = 4), and only four consecutive batch runs were operated. Although we did not use an industrial ${\beta}$-gal for GOS production, in which a thermophile is used routinely, this represents the longest operation time for GOS production using E. coli ${\beta}$-gal. Improved stability and durability of the cell immobilization system were achieved using the crosslinking protocol. This strategy could be directly applied to other microbial enzyme reactor systems using cell immobilization to extend the operation time and/or improve the reactor system stability.

• 공업화학
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• 제31권3호
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• pp.328-333
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• 2020

본 연구에서는 PFO와 Coal-tar의 구조와 열 중합 거동 분석을 통해 PFO와 Coal-tar으로 구성된 혼합 원료의 피치 합성 간 제조 특성을 확인하였다. 원소분석과 FT-IR 분석을 통해, PFO와 Coal-tar 각각 0.355, 0.818로 방향족화도 수치를 확인하였다. 또한, PFO와 Coal-tar의 열중량 분석을 통해 질량 감소곡선의 차이를 확인하였으며, 이러한 현상은 방향족 화도와 관능기 함량에 따른 구조적 안정성에 기인한 것으로 판단된다. 피치 제조 특성은 PFO를 원료로 사용한 피치가 혼합원료로부터 제조된 피치보다 평균적으로 낮은 수율과 높은 연화점을 보임을 확인하였다. 특히 유사한 연화점을 가지는 P360 (138.5 ℃)과 B420 (141.4 ℃)을 비교하였을 때, 두 피치의 탄화수율은 각각 29.89, 49.03 wt%로 Coal-tar가 혼합된 경우 약 20 wt% 향상됨을 확인하였다. 이러한 결과는 다량의 알킬기를 포함하여 높은 피치 중합 반응성을 가지는 PFO와 높은 열적 안정성을 가지는 Coal-tar의 혼합에 기인한 것으로 판단된다.

• 한국미생물·생명공학회지
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• 제16권4호
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• pp.327-333
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• 1988

대장균을 이용한 재조합 인체 인터루킨-2(IL_2) 생산의 최적화를 위하여 발효조건이 세포성장과 IL-2의 생산 및 재조합 세포의 안정성 등에 미치는 영향을 조사하였다. 복합배지의 경우에는 yeast extract, peptone, corn steep liquor 등이 재조합 세포성장에 좋은 효과를 나타내었다. 재조합 세포의 안정성은 IL-2 발현 억제 조건(3$0^{\circ}C$)에서는 안정하게 유지되었으나 IL-2 생산조건(42$^{\circ}C$)에서는 selection pressure를 주었을 때조차도 현격하게 감소함을 알 수 있었다. 한편 배양배지에 항생제를 첨가한 경우에도 안정성 유지에는 별로 도움이 되지 못하고 세포성장만 억제됨을 알 수 있었다. 유전자의 발현은 대수 증식 중기에서 유도했을 때가 IL-2 생산에 가장 좋은 것으로 나타났으며 IL-2 생산은 세포성장과 플라스미르내의 다른 유전자들의 발현을 상당히 저해시킴을 알 수 있었다.

• 한국태양에너지학회 논문집
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• 제36권1호
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• pp.49-61
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• 2016

The power production using hub height wind speed tends to be overestimated than actual power production. It is because the hub height wind speed cannot represent vertical wind shear and blade tip loss that aerodynamics characteristic on the wind turbine. The commercial CFD model WindSim is used to compare and analyze each power production. A classification of atmospheric stability is accomplished by Monin-Obukhov length. The concentric wind speed constantly represents low value than horizontal equivalent wind speed or hub height wind speed, and also relevant to power production. The difference between hub height wind speed and concentric equivalent wind speed is higher in nighttime than daytime. Under the strongly convective state, power production is lower than under the stable state, especially using the concentric equivalent wind speed. Using the concentric equivalent wind speed considering vertical wind shear and blade tip loss is well estimated to decide suitable area for constructing wind farm.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.193-194
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• 2008

$Orgacon^{TM}$ products, based on the conducting polymer PEDOT/PSS, are very promising materials in cost-effective R2R production of large area electronics. This presentation will show both the progress in the surface resistance/VLT and progress in the stability (T/R.H. and light stability). A new generation of films, coating formulations and inks will be presented.

• 수산해양기술연구
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• 제47권3호
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• pp.241-247
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• 2011

Marine casualties of vessel are said to be in most case caused by human error, but it would be valid for the assumption that the ship is built with high quality and then should be acceptable to the safety standards. It means that the inherent characteristics of a ship should be the first consideration on the safety of ship. Therefore it is basically necessary for navigator to grasp the inherent stability of his ship and ensure that the ship complies with the minimum statutory standards of stability. This study is to realize the stability of the Korean offshore large purseiner varying with loading conditions by the inclining data and some calculations. The author compared the stability of the ship with IMO criteria and domestic rule, and proposed some improvement for the safety of the ship. The results are summarized as follows ; The values of GM of the ship according to the loading condition in navigation satisfy both of the IMO criteria and the domestic rule, but in case of the area under the GZ curves between the heel angles of $30^{\circ}$ and $40^{\circ}$, and the heel angle occuring the maximum righting lever not satisfy the IMO rule at the fishing ground departure and arrival conditions in the haul in net situation. The initial metacentric height of the ship is very large, but the range of stability and the occurring angle of the maximum GZ are very small, so even small inclining can bring about the beam end. The best method of improvement for that is to increase the freeboard of the model among the variables.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.96-104
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• 2000

It is well known that combustion stability under idle and part-load conditions directly affect fuel economy and exhaust emission. In practice, there have been a lot of studies so that a significant improvement in combustion stability has been achieved in this research field. However, applying published results to the development process of mass production engine, there are still many problems which are solved previously. In this study, initial flame behavior and flame propagation characteristic were investigated statistically in order to optimize combustion chamber shapes in the development stage of mass production S.I. engine. To the purpose, the authors applied the flame image capturing system to single cylinder optical engine. The captured flame images were effectively analyzed by using the image processing program which was developed by the authors and adopted new threshold algorithm instead of conventional histogram analysis. In addition, the cylinder pressure was also measured simultaneously to compare evaluated flame results with cylinder pressure data in terms of the combustion characteristics, combustion stability, and cycle-to-cycle combustion variability.