• Journal of fish pathology
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• v.19 no.1
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• pp.65-72
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• 2006

Nervous necrosis virus (NNV) that causes severe mortality during seed production of red drum (Sciaenops ocellatus) is known to be vertically transmitted from infected spawners. This study was conducted to produce NNV free seeds by testing spawners for NNV infection and using virus free eggs for seed production. RT-PCR analysis of 40 spawners showed 18 positives and 22 negatives. NNV was not detected from eggs obtained from the negative spawners but was detected from those obtained from the positives. NNV was not detected from culturing seawater in tanks and Chlorella spp., Brachionus plicatilis., and Brine shrimp those were provided as live feed. The survival rates of fry from NNV positive and negative spawners were 80% and 85%, respectively by two weeks after hatching. The mortality increased from 25days after hatching and the final survival rate of seeds from NNV positive and negative spawners were 0% and 18.3%, respectively on 41 days after hatching. These results suggested that virus free red drum seeds can be obtained by using virus-free spawners.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2002.10a
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• pp.21-31
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• 2002

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.524-525
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• 2006

• The Journal of the Korean Society for Microbiology
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• v.1 no.1
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• pp.33.2-33.2
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• 1958

• Proceedings of the Korean Society of Life Science Conference
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• 2001.02a
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• pp.76-76
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• 2001

• Journal of the KSME
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• v.29 no.2
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• pp.169-174
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• 1989

기계의 운전 중에 불평형이 변화할 확률은 예측하기가 어렵다는 것에 대해서는 이미 지적한바 있다. 따라서 계산은 미감도의 평가로 한정된다. 이 값은 공진에 인접하여 운전될 때의 특수 한 경우에 대한 것이다. 계산의 정확도를 지나치게 높이 평가하지 않도록 주의할 필요가 있다. 이러한 속도에서 계의 감쇠는 특히 중요하며, 복잡한 계에 있어서는 충분한 정확도를 갖도록 이 감쇠값을 계산할 수는 없다. 따라서, 설계자는 감쇠값의 결정에 있어서 부분적으로 경험에 의 존해야 한다.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.1-8
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• 2005

Civil aviation regulation such as FAR and loads analysis procedure based on this was explained, and loads analysis procedure and results for Smart UAV was presented for application case. For loads analysis, applicable regulations and loads conditions should be prepared in advance, and modeling for aerodynamics, weight, and structure should be performed. Panel method is usually adopted for aircraft loads analysis to obtain aerodynamic loads. In this study, ARGON which is multidisciplinary fixed wing aircraft design software co-developed by KARI and TsAGI was used for loads analysis. ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis of 4-seater canard airplane was performed with ARGON and that results were presented.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.4
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• pp.506-514
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• 2005

Unaccounted-for water subtracting water sold from produced water includes leakage, under-registration, unauthorized use, etc. To improve accounted-for water ratio, firstly, it should be attempted to accurately identify where unaccounted-for water is, and then it must to be reduced. Under-registration of meter is caused by allowable tolerance of meter, improper size of meter installed, gradient installation, etc. Under-registered water of meters has ever been the second large amount of unaccounted-for water next to leakage, but still is not estimated exactly. In this study, the estimated value as under-registered water was obtained by using the selected-area modeling program. As a result, the under-registered water ratio of 13mm meters was approximately 1.23%. Those of meters according to ages 1, 3, and, 5 years old were 1.46% 2.77% and, 2.26%, respectively but that of 7 years old meters showed over-registration of 1.59%.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.582-594
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• 2005

The under-registration of water meters of 20mm to 50mm in diameter, installed in Seoul city, was estimated by random sample method. The sample sites and sampled meters were selected for the measurements of flow rates and accuracy tests, respectively. The measurement of flow rates was conducted for 20mm to 50mm meters for about 20 days per site using flow meters and data loggers. The under-registration of 20mm, 25mm, 32mm, 40mm, and 50mm meters was observed as 3.96%, 1.10%, 2.47%, 4.04%, and 1.04%, respectively. The under-registration might be increased more or less as malfunction and failure of the sampled meters was not considered. In this study the under-registration of 20mm, 25mm, 32mm, 40mm, and 50mm meters was accurately estimated on the basis of the investigation data. The estimation of under-registration of water meters, one of the basic figures in water industry, contributed to accurate calculation of leakage, water supply and consumption, and strategic planning to reduce the unaccounted-for water.

• The Journal of the Acoustical Society of Korea
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• v.6 no.1
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• pp.58-65
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• 1987

The audible tones of switching system employed in the country at present do not only disagree with CCITT Recommendation Q35, but also are different in the specifications and the sense of hearing. Such a discord with the specifications and the sense of hearing causes a subscriber and an operator to confuse. In this paper characteristics of the sense of hearing of them and the accuracy of tone specifications are studied and novel unified audible specifications are proposed. And it is showed that the digital tone generation of digital switching systems can be implemented readily, using a ROM.