• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.285-288
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• 2004

This study presents a numerical procedure to optimize the shape of dimple surface to enhance turbulent heat transfer in rectangular channel. The response surface based optimization method is used as an optimization technique with Reynolds-averaged Wavier-Stokes analysis of fluid flow and heat transfer with shear stress transport (SST) turbulence model. The dimple depth-to -dimple print diameter ratio, channel height- to- dimple print diameter ratio. and dimple print diameter-to-pitch ratio are chosen as design variables. The objective function is defined as a linear combination of heat transfer coefficient and friction drag coefficient with a weighting factor. Full factorial method is used to determine the training points as a mean of design of experiment.

• 인간식물환경학회지
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• 제24권6호
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• pp.629-638
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• 2021

Background and objective: This study was conducted to develop diameter growth models for thinned Quercus glauca Thunb. (QGT) stands to inform production goals for treatment and provide the information necessary for the systematic management of this stands. Methods: This study was conducted on QGT stands, of which initial thinning was completed in 2013 to develop a treatment system. To analyze the tree growth and trait response for each thinning treatment, forestry surveys were conducted in 2014 and 2021, and a one-way analysis of variance (ANOVA) was executed. In addition, non-linear least squares regression of the PROC NLIN procedure was used to develop an optimal diameter growth model. Results: Based on growth and trait analyses, the height and height-to-diameter (H/D) ratio were not different according to treatment plot (p > .05). For the diameter of basal height (DBH), the heavy thinning (HT) treatment plot was significantly larger than the control plot (p < .05). As a result of the development of diameter growth models by treatment plot, the mean squared error (MSE) of the Gompertz polymorphic equation (control: 2.2381, light thinning: 0.8478, and heavy thinning: 0.8679) was the lowest in all treatment plots, and the Shapiro-Wilk statistic was found to follow a normal distribution (p > .95), so it was selected as an equation fit for the diameter growth model. Conclusion: The findings of this study provide basic data for the systematic management of Quercus glauca Thunb. stands. It is necessary to construct permanent sample plots (PSP) that consider stand status, location conditions, and climatic environments.

• Journal of the Korean Wood Science and Technology
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• 제43권2호
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• pp.145-155
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• 2015

Fiber morphology and basic characteristics of Legi bamboos (Gigantochloa atter) growing on Yogyakarta were studied considering their age and height positions in the culms. Culms of 4, 16, and 40 months were harvested, and their total lengths were measured. The length, diameter, and wall thickness of each internode were measured. All the sample culms were divided into three different parts along the height, and their fiber dimension and physical properties were observed. The data obtained were analyzed by analysis of variance. The results showed that the culms had a diameter of 5.8 to 10.8 cm. The lowest internodes always showed the shortest length and the thickest wall. The culms had an average fiber length of 2.41 mm and Runkel ratio of 0.61. Fiber length was affected by the height, while fiber diameter, lumen diameter, and fiber wall thickness were affected significantly by the age of the culms. The culms had high green moisture content (GMC) of 157.89%, and basic density (BD) of $456.67kg.m^{-3}$, a total longitudinal shrinkage of 0.35%, and relatively low R/T shrinkage ratio. The interactions between age and height were affected GMC and BD.

• 공업화학
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• 제9권6호
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• pp.901-906
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• 1998

기체분산기로 단일노즐을 사용한 내부순환 공기리프트 반응기에서 기체 및 액체의 유동특성을 해석하였다. 실험은 공기-물계에서 하강관의 직경과 상승관의 높이가 다른 세 가지 반응기를 사용하여 기체속도와 반응기의 높이를 변화시키면서 각 유동지역의 기체체류량과 추적자의 충격-응답곡선을 측정하였다. 실험결과, 기포의 유동양상은 상승관에서 강한 기포합체를 일으키는 슬러그흐름을, 그리고 하강관에서는 직경의 크기에 따라 전이흐름 또는 균일상 기포흐름을 나타내었다. 그리고 동일한 반응기 상부지역의 높이비에서 각 유동지역과 반응기 전체의 평균 기체체류량은 하강관의 직경이 작을수록 상당히 증가하였다. 또한 혼합시간은 기체속도보다 반응기 상부지역의 높이에 크게 영향을 받으며 동일한 반응기 상부지역의 높이비에서는 하강관의 직경과 상승관의 길이가 클수록 상당히 큰 값을 나타내었다. 액체의 유동특성은 하강관에서 기포의 유동양상과 반응기 상부지역의 크기에 따라 크게 변화하였으며 상승관에서 액체의 순환속도는 기체속도와 반응기 상부지역의 크기가 증가할수록 증가하였고 동일한 반응기 상부지역의 높이비에서는 하강관의 직경과 상승관의 길이가 증가할수록 증가하였다.

• 한국자원식물학회지
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• 제22권4호
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• pp.299-303
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• 2009

넓은잎큰조롱의 두둑높이에 따른 생산성 및 품질향상을 위하여 재배법 확립의 기초자료로 제공하고자 두둑높이를 달리하여 2005년부터 3년간 시험한 결과, 만장, 엽장, 엽폭, 엽수, 엽록소함량, 경엽 건물중은 두둑높이가 높을수록 양적인 증가를 가져왔으나, 경태와 분지수는 두둑높이가 낮을수록 굵거나, 많은 경향이었다. 근수와 근장은 두둑높이 20 cm까지는 두둑높이가 높을수록 많거나, 길었으나, 20 cm 이상의 두둑높이에서는 생육량이 감소하였으며, 근태는 두둑높이가 낮을수록 굵어지는 경향이었다. 비상품근 중 세근은 두둑높이 20 cm에서 다소 많았으며, 부패근은 두둑높이가 낮을수록 많은 경향이었고, 근수량은 두둑높이 20 cm내지 30 cm 까지는 두둑높이가 높을수록 증수되어 두둑높이 10 cm의 515 kg/10a 대비 3%, 11% 증수되었다.

• 한국유체기계학회 논문집
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• 제15권4호
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• pp.19-26
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• 2012

In this paper, a parametric study on ribs which are installed in an equilateral triangular internal cooling channel is presented. The numerical analysis of the flow structure and heat transfer characteristics is performed using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The numerical results are obtained at Reynolds number, 20,000. The parametric study is performed for the parameters, the angle of a rib, rib pitch-to-hydraulic diameter ratio, rib width-to-hydraulic diameter ratio, and rib height-to-hydraulic diameter ratio. The computational results are validated with the experimental data for area-averaged Nusselt number.

• Geomechanics and Engineering
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• 제11권3호
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• pp.385-400
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• 2016

Bearing capacity of open-ended piles depends largely on inner frictional resistance, which is influenced by the degree of soil plugging. While a fully-plugged open-ended pile produces a bearing capacity similar to a closed-ended pile, fully coring (or unplugged) pile produces a much smaller bearing capacity. In general, open-ended piles are driven under partially-plugged mode. The formation of soil plug may depend on many factors, including wall thickness at the pile tip (or inner pile diameter), sleeve height of the thickened wall at the pile tip and relative density. In this paper, we studied the effects of wall thickness at the pile base and sleeve height of the thickened wall at the pile tip on bearing capacity using laboratory model tests. The tests were conducted on a medium dense sandy ground. The model piles with different tip thicknesses and sleeve heights of thickened wall at the pile tip were tested. The results were also discussed using the incremental filling ratio and plug length ratio, which are generally used to describe the degree of soil plugging. The results showed that the bearing capacity increases with tip thickness. The bearing capacity of piles of smaller sleeve length (e.g., ${\leq}1D$; D is pile outer diameter) was found to be dependent on the sleeve length, while it is independent on the sleeve length of greater than a 1D length. We also found that the soil plug height is dependent on wall thickness at the pile base. The results on the incremental filling ratio revealed that the thinner walled piles produce higher degree of soil plugging at greater penetration depths. The results also revealed that the soil plug height is dependent on sleeve length of up to 2D length and independent beyond a 2D length. The piles of a smaller sleeve length (e.g., ${\leq}1D$) produce higher degree of soil plugging at shallow penetration depths while the piles of a larger sleeve length (e.g., ${\geq}2D$) produce higher degree of soil plugging at greater penetration depths.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.70.1-70
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• 2001

• 사상체질의학회지
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• 제10권2호
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• pp.221-270
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• 1998

Objective This research is a study about constitutional diagnosis through the external appearances as a basic principle, and it is for finding shape differences of the ear, eye, nose, mouth according to the Sasang constitution Method We have collected 209 cases of patients of the Sasang Constitutional Department, including employees of the Kyung-Hee Medical Center and took pictures of the frontal view, lateral view, oblique view of face and measured heights, deapth, breadths of ear, eye, nose, mouth with 'The Measurement of R. Martin'. We analyzed shape differences of the face according to the Sasang constitution with certain results Results We got the morphologic characteristics of ear, eye, nose and mouth according to the Sasang constitution as Table 3. -Table 10. Conclusion : 1. The morphologic characteristics of Ear according to the Sasang constitution (1) Morphologic ear length, Physiognomic ear length, Ear lobule length is longer in Taeumin than Soeumin. (2) Physiognomic ear breadth is wider in Taeumin than Soeumin. (3) Physiognomic ear length, lobule length ratio is higher in Taeumin than Soyangin. 2. The morphologic characteristics of Eye according to the Sasang constitution. (1) Inner Palpebral fissure width, 5th Palpebral fissure length, Bizygomatic breadth-Outercanthal distance is the longest in Taeumin (2) Palpebral fissure inclination is widest in Soeumin. (3) Palpebral fissure length is longer in Taeumin than Soeumin. (4) Pupillary diameter ratio is the lowest in Taeumin (5) Palpebral fissure length, width ratio is higher in Soeumin than Taeumin. (6)zygomatic breadth, Bizygomatic breadth-Outercanthal distance ratio is the higher in Taeumin than Soeumin. 3. The morphologic characteristics of Nose according to the Sasang constitution. (1) Nasion depth is deepest in Soyangin. (2) Nasion to pupillary depth is deeper Soyangin than Taeumin. (3) Nasal tip depth, Nostril to Nasalalar depth is deeper Soyangin than Taeumin. (4) Subnasale to Nasalalar depth is the shallowest in Taeumin (5) Nasalalar height is lowest in Soeumin. (6) Nasalalar to Nostril distance is deeper Taeumin than Soeumin. (7) Nasal tip depth, Nasal depth ratio is the highest in Taeumin (8) Nasal depth Nasalalar heightratio is lowest in Soeumin. (9) Midfaceheight, Nasal tip depth ratio is higher Soyangin than Taeumin. 4. The morphologic characteristics of mouth according to the Sasang constitution. (1) Lower mid lip height, Lower philtrum height, Lower quarter lip height, Total middle lip height, Total philtrum height, Total quarter lip height is the shottest in Soyangin. (2) Upper mid lip height, Upper philtrum height is longer in Taeumin than Soyangin (3) Lip inclination is higher in Soeumin than Soyangin. (4) Intercheilion breadth, total height ratio is lowest in Soyangin. (5) Total lip height, Upper philtrum height ratio is higher in Soyangin than Soeumin. (6) Lower lip height Lower quarter lip height ratio is higher in Soyangin than Taeumin. (8) Total lip area is wider in Taeumin than Soyangin.

• Advances in concrete construction
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• 제13권3호
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• pp.223-231
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• 2022

The problem is formulated by applying the Kirchhoff's conception for shell theory. The longitudinal modal displacement functions are assessed by characteristic beam ones meet clamped-clamped end conditions applied at the shell edges. The fundamental natural frequency of rotating functionally graded cylindrical shells of different parameter versus ratios of length-to-diameter and height-to-diameter for a wide range has been reported and investigated through the study with fractions laws. The frequency first increases and gain maximum value with the increase of circumferential wave mode. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing height-to-radius ratio. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases. The trigonometric frequencies are lower than that of exponential and polynomial frequencies. Stability of a cylindrical shell depends highly on these aspects of material. More the shell material sustains a load due to physical situations, the more the shell is stable. Any predicted fatigue due to burden of vibrations is evaded by estimating their dynamical aspects.