• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.380.1-380
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• 1999

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.301-307
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• 2012

The characteristics of pressure loss in an asymmetric bifurcating tube were investigated numerically for steady inspiratory conditions. The loss coefficient K calculated for various asymmetry and flow-distribution ratios found in human lung airways showed a power-law dependence on the Reynolds number (Re) and length-to-diameter ratio (L/d), with different exponents for Re $\geq$ 100 and Re < 100. The fundamental characteristics of the asymmetric bifurcation are similar to the case of symmetric bifurcation. In addition, the effect of skewed inlet velocity profiles on the pressure loss was weak, and decreased with an increasing number of bifurcations.

• Journal of Korea Multimedia Society
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• v.9 no.9
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• pp.1131-1138
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• 2006

This paper proposes a novel method for grading of underground communication conduits by laser projection image analysis. The equipment thrust into conduit consists of a laser diode, a light emitting diode and a camera, the laser diode is utilized for generating projection image onto pipe wall, the light emitting diode for lighting environment and the image of conduit is acquired by the camera. In order to segment profile region, we used a novel color difference model and multiple thresholds method. The shape of profile ring is represented as a minimum diameter and the Fourier descriptor, and then the pipe status is graded by the rule-based method. Both local and global features of the segmented ring shaped, the minimum diameter and the Fourier descriptor, are utilized, therefore injured and distorted pipes can be correctly graded. From the experimental results, the classification is measured with accuracy such that false alarms are less than 2% under the various conditions.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.55-65
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• 2002

Model tests were performed to investigate the mechanism of lateral earth pressure on a buried pipe, which was installed in a plastic flowing soil mass undergoing lateral movement. On the basis of failure mode tests, the equation of lateral earth pressure to apply Maxwell's visco-elastic model was proposed to consider the soil deformation velocity. Through a series of model tests of differential soil deformation velocity, lateral earth pressure of theoretical equation was compared with experimental results. When lateral soil movement was raised, the lateral earth pressure acting on buried pipe increases linearly with the soil deformation velocity. It shows that the lateral earth pressure on buried pipe is largely affected by soil deformation velocity. When plastic soil movement was raised, lateral earth pressure predicted by theoretical equation showed good agreement with experimental results. Also, coefficient of viscosity by theoretical equation had a good agreement with direct shear test results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.5 no.1
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• pp.51-56
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• 1969

Fourty lines of F4 progenies of an Adzuki bean cross, Jukdoo (Korean local variety) X Nesumimochi (Japanese variety) were used as the material, and these lines were grown in replicated trials in 1967. Phenotypic, genotypic and environmental covariances among all possible traits of eight character are calculated as shown in table 1. Phenotypic, genotypic and environmental correlations among all possible paris of eight characters were calculated as shown in table 2. In general, genotypic correlations were higher than the corresponding phenotypic corresponding phenotypic correlations. The genotypic correlations between seed yield (grain weight per plot) and oter agronomic characters indicated that seed yield was genetically associated with the character of pod number per plant, and grain number per plant, which is closely correlated with pod number pr plant, are affected more in Adzukl bean yield than the other agronomic characteracters.

• Environmental engineer
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• s.323
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• pp.86-95
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• 2013

본 발명은 해수의 담수화 장치에 관한 것으로, 해수를 증기와 온수로 변환하도록 태양열을 이용하여 상기 해수를 가열하는 가열기와, 상기 가열기에 의해 변환된 상기 증기와 상기 온수를 분리하는 분리기를 포함하며, 상기 가열기는, 오목한 곡면을 갖는 반원통 형상으로 마련되고, 상기 반원통 형상의 길이방향을 따라 위치하는 다수의 초점을 향하여 내면으로 조사된 태양광을 반사하는 반사렌즈 및 상기 반사렌즈에 의해 반사된 상기 태양광의 열 에너지에 의해 상기 해수를 가열하도록, 상기 반사렌즈의 초점이 위치하는 길이방향의 지점을 따라 상기 해수가 흐를 수 있도록 형성되는 유로관을 포함하는 것을 특징으로 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.373-374
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.311-311
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• 2004

1960년 레이저가 발명된 이래 레이저의 응용연구가 많은 비중을 차지하여 오늘날 다양한 방면에서 레이저가 필수적인 장치로 각광을 받게 되었다. 레이저의 특성들 중에서 특히 직진성, 에너지 집중도 및 고휘도성을 이용하여 용접, 절단, 각인 등의 산업적 응용에 많이 활용되고 있다 그 중 레이저가 보통의 빛과 같이 투명한 물체를 통과하고 특수한 렌즈를 이용하면 투명한 물체의 내부에 초점을 맞춰 크랙(crack)을 낼 수 있는 바 이를 이용하여 크리스탈이나 유리의 내부에 2차원 형상이나 3차원 형상을 각인시킬 수 있다.(중략)

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1004-1006
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• 2010

차량에 사용되는 무시동 히터 열교환기의 효율 개선을 위하여 열전달 해석을 수행하였다. 연구에 사용된 히터는 연료 공급관을 통해 연소부로 연료를 공급하고 연소시켜, 열교환기에 열을 전달한다. 열전달 효율을 증대시키기 위하여 열전달면 및 연소면의 형상을 해석적으로 개발하였다. 개선된 열교환기 모델은 외부 형상을 기존 제품과 동일하게 설계하여 단품상으로 교체가 가능하도록 설계 하였다. 해석 결과 기존 모델에 대비 개선된 모델에서 열전달 효율이 약 5.6배 향상되었다.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.811-821
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• 2003

In this study is if the design of outlet conduit was appropriate or not by analyzing flow characteristic of outlet conduit with performing hydraulic model experiments. As the results of hydraulic model experiments, the capacity of outlet conduit of elementary design was under estimated, and the designed values of the capacity of outlet conduit of preliminary design based on the values of elementary design was nearly equal to the values of experiments, so the propriety of design was identified. In addition, as the results of examinations of negative pressure of outlet conduit, and propriety of longitudinal sections, the resulting values were within the maximum permissible limits, so it was proved that the design was appropriate. In the base of such processes, the propriety of scale and location of outlet conduit of preliminary design was examined.