• ALGAE
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• 제17권1호
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• pp.1-9
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• 2002

Diel vertical distribution of phytoflagellates and interactions between the phytoplankton components and environmental and biological factors were studied in a small artificial pond for three days on the December 18, 1998 and April 9 to 10, 1999. The phytoplankton population was dominated by Mallomonas akrokomos of chrysophytes and Cryptomonas marssonii and Chroomonas sp. of cryptophytes. The vertical distribution of these phytoflagellates taxa exhibited clear diel migration pattern. Moreover their migration patterns are showed differential fluctuation between M. akrokomos, C. marssonii and Chroomonas sp. The later two species upward migrated in the evening as well as night, whereas the former species migrated downward. Their distinctive migration pattern was found during the night but was not observed in the morning. During daytime C. marssonii and Chroomonas sp. showed maximum density above 2 m depth but M. akrokomos below 2 m depth. The diel vertical distribution of the dominant phytoflagellates did not show significant correlation between physical, chemical and biotic factors.

• Nuclear Engineering and Technology
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• 제36권3호
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• pp.203-209
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• 2004

In-phantom neutron flux distribution is measured at the HANARO BNCT irradiation facility. The measurements are performed with Au foil and wires. The thermal neutron flux and Cd ratio obtained at the HANARO BNCT facility are $1.19{\times}10^9\;n/cm^{2}s$ and 152, respectively, at 24 MW reactor power. The measured in-phantom neutron flux has a maximum value at a depth of 3 mm in the phantom and then decreases rapidly. The maximum flux is about $25\%$ larger than that of the phantom surface, and the measured value at a depth of 22 mm in the phantom is about a half of the maximum value. In addition, the neutron beam is limited well within the aperture of the neutron collimator. The two-dimensional in-phantom neutron flux distribution is determined. Significant neutron irradiation is observed within 20 mm from the phantom surface. The measured neutron flux distribution can be utilized in irradiation planning for a patient.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.93-98
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• 2001

This study was performed to analyse the rainfall and the rainfall-runoff characteristics of a rural watershed. The Sangwha basin($105.9km^{2}$) in the Geum river system was selected for this study. The arithmetic mean method, the Thiessen's weighing method, and the isohyetal method were used to analyse areal rainfall distribution and the Huff's quartile method was used to analyse temporal rainfall distribution. In addition, daily runoff analyses were peformed using the DAWAST and tank model. In the model calibration, the data from June through November, 1999 were used. In the model calibration, the observed runoff depth was 513.7mm and runoff rate was 45.2%, and the DAWAST model simulated runoff depth was 608.6mm and runoff rate was 53.5%, and the tank model runoff depth was 596.5mm and runoff rate was 52.5%, respectively. In the model test, the data from June through November, 2000 were used. In the model test, the observed runoff depth was 1032.3mm and runoff rate was 72.5%, and the DAWAST model simulated runoff depth was 871.6mm and runoff rate was 61.3%, and the tank model runoff depth was 825.4mm and runoff rate was 58%, respectively. The DAWAST and tank model's $R^{2}$ and RMSE were 0.85, 3.61mm, and 0.85, 2.77mm in 1999, and 0.83, 5.73mm, and 0.87, 5.39mm in 2000, respectively. Both models predicted low flow runoff better than flood runoff.

• 방송공학회논문지
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• 제22권1호
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• pp.42-50
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• 2017

비트의 심도 확장은 영상을 표현하는 비트 수를 확장하는 방법이다. HDR(High Dynamic Range) 디스플레이의 발전과 디스플레이의 해상도가 높아짐에 따라서, 디스플레이에서 영상을 표현하는 휘도가 증가하고 표현력도 상승한다. 이러한 디스플레이에 대응하기 위해서는 영상을 표현하는 비트수도 확장되어야 하기 때문에 비트의 심도 확장의 중요성은 높아지고 있다. 본 논문에서는, 높은 비트 심도(10bit)를 가지는 디스플레이에 기존의 영상(8bit)을 자연스럽게 표현하기 위한 비트 심도 확장 방법을 소개한다. 정량적인 결과와 정성적인 결과 및 연산량의 비교를 통해서 제안된 알고리즘이 기존의 비트 심도 확장 방법과 비교해서 우수함을 검증하였다. 제안된 방법은 기존의 최신 비트 심도 확장 방법과 비교해서, 40배 더 빠른 연산속도와 평균 1db이상 높은 성능 향상 결과를 보여준다.

• 지구물리와물리탐사
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• 제10권3호
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• pp.211-218
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• 2007

본 연구는 2003년부터 2004년에 걸쳐 대한광업진흥공사에서 수행한 지하수기초조사의 사업지역인 경남 밀양 및 경기 포천의 지역별 충적층 두께 분포 특성을 파악하기 위하여 전기비저항 수직탐사(슐럼버져 배열)에 의해 획득된 충적층 심도 자료에 대하여 지구통계학적 기법인 정규크리깅을 적용하였다. 물리탐사 자료의 적용성 검증을 위하여 물리탐사 자료와 시추공 자료의 상관성분석을 실시하였다. 정규크리깅에 의해 충적층 분포를 이미지화한 결과, 지형이나 유역에 따라 충적층 심도분포가 합리적으로 묘사된 것으로 나타났으며, 따라서, 충적층 심도 분포 파악에 있어서 전기비저항 수직 탐사 자료에 의해서도 만족할만한 수준의 결과를 얻는 것이 가능한 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1296-1305
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• 2008

In this study, the spatial distribution of depth between alluvial soil and weathered soil of Song-do new city is analyzed using geostatistics. From analysis results, the boundary depth of north-east region is deeper than that of south-west region, and average depth of north-east region is 27.14m and average depth of south-west region is 23.25m. The boundary depth is estimated by ordinary kriging and inverse distance method, and estimated results are almost similarity. So, in Song-do new city, these two method can be used to estimate the boundary depth. The ordinary kriging method is a very useful tool because the more exact analysis of spatial continuity and distribution characteristic is possible.

• 설비공학논문집
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• 제18권10호
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• pp.800-810
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• 2006

The R-134a flow distribution is experimentally studied for a heat exchanger composed of round headers and 10 flat tubes. The effects of tube protrusion depth as well as mass flux, and quality are investigated, and the results are compared with the previous air-water results. The flow at the header inlet is stratified. For the downward flow configuration, the liquid distribution improves as the protrusion depth or the mass flux increases, or the quality decreases. For the upward configuration, the liquid distribution improves as the mass flux or quality decreases. The protrusion depth has minimal effect. For the downward configuration. the effect of quality on liquid distribution is significantly affected by the flow regime at the header inlet. For the stratified inlet flow, the liquid is forced to rear part of the header as the quality decreases. However, for the annular inlet flow, the liquid was forced to the frontal part of the header as the quality decreased. For the upward flow, the effect of the mass flux or quality on liquid distribution of the stratified inlet flow is opposite to that of the annular inlet flow. The high gas velocity of the annular flow may be responsible for the trend. Generally, the liquid distribution of the stratified inlet flow is better than that of the annular inlet flow. Possible explanation is provided from the flow visualization results.

• 한국초지조사료학회지
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• 제11권4호
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• pp.215-221
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• 1991

혼파된 영년채초지에서의 예취빈도와 질소시비가 뿌리의 수량과 심층분포에 미치는 영향에 대하여 연구된 결과는 다음과 같다. 1. 조사된 식생구조에서의 뿌리의 분포는 모든 처리구에서 상층 20cm까지에 그 대부분이 존재하였다. 2. 뿌리의 양은 우점종에 관계없이 모두 높았지만 Arrhenatherum elatius 우점초지에서 가장 낮았고 Alopecurns pratensis우점초지에서 가장 높았다. 3.뿌리의 양은 예취빈도간에는 그 차이가 없었으나 적당한 N 시비수준(N-2)에서 가장 높았다. 4. 뿌리의 심층분포는 모든 처리구에서 1m 길이까지 존재하였다.

• 한국생산제조학회지
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• 제22권6호
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• pp.931-936
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• 2013

Recently, the use of large-electron-beam polishing for polishing complex metal surfaces has been proposed. In this study, the temperature induced by a large electron beam was predicted using the heat transfer theory. A finite element (FE) model of a continuous wave (CW) electron beam was constructed assuming Gaussian distribution. The temperature distribution and melting depth of an SUS304 sample were predicted by changing electron-beam polishing process parameters such as energy density and beam velocity. The results obtained using the developed FE model were compared with experimental results for verifying the melting depth prediction capability of the developed FE model.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.244-247
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• 2002

We examined a possibility to use inorganic plastic scintillator, which has the effective atomic number close to that of human soft tissue, for the measurement of dose distributions in a shorter time period. The method was to irradiate a block of plastic scintillator as a phantom, and to measure the distribution of the scintillation light by a wave length analyzer through a thread of plastic optical fiber. By irradiating the diagnostic x-ray, we observed the emission spectrum of the scintillation light from the scintillator. It showed a peak at around 420nm with a full width of 140 nm. The emission spectrum was integrated to determine the total number of photons. The dependences of the amount of photons on the irradiated dose were measured. The results of the experiment show that the amount of emission light is in proportional to the irradiated dose. From this fact, we conclude that the present method can be used for the measurement of the depth dose distribution of the diagnostic x-rays.