비선형 k-ε 모형을 이용한 부분 식생 개수로 흐름의 평균흐름 및 난류구조 수치모의

최성욱,최성욱,김태준,Choi, Seongwook,Choi, Sung-Uk,Kim, Taejoon 대한토목학회 2014 대한토목학회논문집 Vol.34 No.3

본 연구에서는 부분 식생된 개수로에서 평균흐름 및 난류구조에 관한 수치모의 결과를 제시하였다. 이를 위하여 식생항력항이 포함된 레이놀즈 평균 Navier-Stokes 방정식을 수치해석 하였고 난류 모형으로 비선형 k-${\varepsilon}$ 모형을 이용하였다. 제시된 모형을 Nezu and Onitsuka (2001)의 실험수로에 적용하여 모의된 결과를 실험 계측자료 및 Kang and Choi (2006)의 Reynolds stress model 모의결과와 비교하였다. 실험결과와 비교한 결과에 따르면, 비선형 k-${\varepsilon}$ 모형이 평균흐름의 대체적인 경향을 잘 모의하는 것으로 확인되었다. 또한, 식생 영역과 비식생 영역의 경계면에서 쌍와 (twin vortices)가 생성되고 난류강도와 레이놀즈 응력의 최대점이 위치하는 것을 확인하였다. 레이놀즈 응력에 대해서는 경향은 잘 모의하지만 정량적으로 과소 산정하는 것으로 나타났다. This study presents a numerical modeling of mean flow and turbulence structures of partly-vegetated open-channel flows. For this, Reynolds-averaged Navier-Stokes equations with vegetation drag terms are solved numerically using the non-linear k-${\varepsilon}$ model. The numerical model is applied to laboratory experiments of Nezu and Onitsuka (2001), and simulated results are compared with data from measurement and computations by Kang and Choi's (2006) Reynolds stress model. The simulation results indicate that the proposed numerical model simulates the mean flow well. Twin vortices are found to be generated at the interface between vegetated and non-vegetated zones, where turbulence intensity and Reynolds stress show their maximums. The model simulates the pattern of the Reynolds stress well but under-predicts the intensity of Reynolds stress slightly.

조명광원의 색온도와 조도 및 스펙트럼 측정

최대욱,박성진,임춘우,석성수,오철한 慶北大學校 師範大學 科學敎育硏究所 1999 科學敎育硏究誌 Vol.23 No.-

The peak wavelength and temperatures of W-Halogen standard light source were measured by using the modified Wien's Law. In the case of graybody, the emissivity ε should be taken into account in using the Wien's Law. In the experiment, PDA spectroscope was used for the measurement of peak wavelength of intensity distribution of spectrum. As the current of light source increases from 5A to 7.4A, the peak wavelength of intensity distribution of the spectrum decreased from 717nm to 690nm, and temperature increased from 3127K to 3330K. Illuminations of three-wavelength lamps and light source were also measured. It was found that irradiation spectrum of those three-wavelength lamps are not coincident to blue(450nm), green(550nm) and red(610nm).

GFRP 보강근을 사용한 콘크리트 프리즘의 직접인장실험

최동욱,이창호,하상수 한경대학교 2005 論文集 Vol.37 No.-

Uniaxial test of Glass Fiber Reinforced Polymer (GFRP) bar reinforced concrete prisms in tension was performed. The objective was to investigate the minimum cover thickness required for the GFRP bars to develop the full rupture strength in tension without developing splitting cracks in concrete. The test variables were bar types (conventional deformed steel rebar and two different GFRP bars) and cover thicknesses (five different clear cover thicknesses ranging between 1 - 3 d_(b)). A total of 15 tests were completed. Normal strength concrete (f_(cu)) = 30.1 MPa) was used. Cracks that appeared on concrete faces were carefully monitored during test and the first cracking loads (both transverse and splitting) were determined. Test results indicated that the adequate cover thickness required for the GFRP bars may be larger than 2 d_(b) while the cover thickness of 2 d_(b) or larger is recommended in ACI 440 committee report. The first split cracking load consistently increased with increasing cover thickness in tests of conventional deformed steel rebars as expected. Such clear tendency was never observed in tests of the GFRP bars indicating possible existence of significant stress being developed in the radial direction, thus causing the concrete splitting to occur.

Effect of Activated Charcoal on Growth of Zingiber mioga ROSC

Choi,Seong-Kyu,Yun,Kyeong-Won,Chon,Sang-Uk,Seo,Young-Nam,Seo,Kyoung-Sun,Kwon,Byung-Sun 한국자원식물학회 2004 Plant Resources Vol.7 No.2

Activate charcoal (AC) can be utilized as a soil conditioner in agricultural crop areas. This study was conducted to investigate the effect of AC on growth and yield of Zingiber mioga ROSC as affected by different amounts of AC. The results obtained are summarized as follows. Growth characteristics including plant height and leaf length were the highest when activated charcoal added with 10-30%, suggesting that optimum amount of activated charcoal was ranged from 10 to 30%. Growth and enlargement of the root were improved by 10% AC with higher rhizome length and weight.

Stacking Crane의 자동 주행을 위한 제어기 설계에 관한 연구

최성욱,김정호,이창훈,이진우,이영진,이권순 동아대학교 정보기술연구소 2001 情報通信硏究所論文誌 Vol.9 No.1

During the operation of crane system in container yard, it is necessary to control the crane trolley position and loop length so that the swing of the hanging container is minimized. Recently an automatic control system with high speed and rapid transportation is required. Therefore, we designed a controller to control the Stack crane system.

Study on Leaf Production of Angelica acutiloba by Mulching with Polyethylene Film

Choi,Seong-Kyu,Yun,Kyeong-Won,Chon,Sang-Uk,Seo,Young-Nam,Seo,Kyoung-sun,Kwon,Byung-Sun 한국자원식물학회 2003 Plant Resources Vol.6 No.3

This study was conducted to produce effectively more leaves of Angelica acutiloba through year-round production system by using various mulching materials and polyethylene(PE) tunnel. Soil temperature by covering treatment was higher in PE mulching and PE tunnel than in rice straw mulching, especially showing the highest temperature in PE tunnel from April through May. Water content of soil was higher in PE mulching than in non-mulching. Leaf production of Angelica acutiloba through year-round production showed the highest in PE tunnel and root production in PE mulching. These results suggest that leaf production of Angelica acutiloba can be maximized through PE tunnel cultivation system.

Effect of Activated Charcoal on Growth of Curcuma longa Linne

Choi,Seong-Kyu,Yum,Kyeong-Won,Chon,Sang-Uk 한국자원식물학회 2003 Plant Resources Vol.6 No.3

This study was conducted to investigate the effect of Activated charcoal (AC) for stimulating growth and productivity of Curcuma longa Linne as affected by different concentrations of AC. Growth characteristics such as plant height and leaf length were the highest with the optimum amount of activated charcoal ranged from 10 to 30%. Root growth was elongated by the addition of 30% AC with the highest rhizome length and weight.

Effect of Storage Condition on Yield and Quality of Angelica acutiloba Radix

Choi,Seong-kyu,Yun,Kyeong-Won,Chon,Sang-Uk,Seo,Young-nam 한국자원식물학회 2002 Plant Resources Vol.5 No.1

To develop an optimal storage method of root of Angelica acutiloba Radix, which has been grown as major herbal medicine material to be cultivated, root of Angelica acutiloba Radix, was stored for 10 months with different packing materials and sealing methods. The loss in dry weight as influenced by packing materials and sealing methods was the lowest at vacuum packing and followed by complete sealing methods with transparent polyethylene film. The ratio of root rot during the storage period was not significantly different between packing materials but was significantly different between sealing conditions. In conclusion, vacuum packing and complete sealing with polyethylene film appears to be most optimal for storage of Angelica acutiloba Radix.

A Basic Study on Leaf and Stem Production of Angelica acutiloba

Choi,Seong-Kyu,Yun,Kyeong-won,Chon,Sang-Uk,Lee,Jong-Ill,Seo,Young-Nam,Seo,Kyoung-Sun,Choi,Kyeong-Ju 한국자원식물학회 2004 Plant Resources Vol.7 No.3

This study was conducted to develop effective production system in greenhouse for leaves and stems of Angelica acutiloba by using connect pots in 2003 and 2004. Seed germination rate and plant biomass of Angelica acutiloba collected in 2004 were higher than those harvested in 2003. Germination rate of Angelica acutiloba seeds collected in 2003 was 10%, while germination rate of seeds collected in 2004 was above 90%. Especially, plant growth and yield of Angelica acutiloba grown in connect pots sized with 4×4×5cm(length×width×height) were the highest. These results indicate that leaf and stem production of Angelica acutiloba can be improved by using connect pots and optimizing seed collecting time in greenhouse.

신축이음장치에서 앵커의 인발 성능 및 나사 풀림 방지를 위한 앵커 시스템 개발

하상수;최동욱 한경대학교 2008 論文集 Vol.40 No.-

The failure of expansion joint for bridge generally occurrs in the non-shrinking mortar while other problem is the release of anchors in expansion joint due to the impact and vibration by traffic on the bridge. In this study, to overcome the failure of expansion joint by the failure of mortar, the elastic mortar is developed. The pull-out capacity of developed elastic mortar was compared with that of non-shrinking mortar. Moreover the anchor system which can be changed easily and prevent a fracture of expansion joint is developed 교량 신축이음장치의 파손 유형은 주로 후타재(무수축 모르타르)와 관련된 부분에서 많이 발생된다. 또 다른 문제는 중차량 통과에 따른 충격과 진동하중으로 인해서 신축이음장치를 후타재에 고정하기 위해서 사용하는 앵커 풀림 현상이다. 본 연구에서는 무수축 모르타르의 파괴에 따른 신축이음장치의 파손을 방지하기 위해 탄성콘크리트를 개발하였다. 개발된 탄성콘크리트와 현재 주로 사용하고 있는 무수축 모르타르의 인발성능을 비교하였다. 또한, 후타재와 신축이음장치를 일체화하여 후타재의 파손을 방지하고 신축이음장치를 쉽게 교체할 수 있는 앵커 시스템을 개발하였다