• 한국지반환경공학회 논문집
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• 제9권3호
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• pp.5-9
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• 2008

하수관거는 지중에 매설되기 때문에 균열발생 시 오염원이 빠르게 지하로 침투되어 오염을 야기한다. 본 연구에서는 하수관거 균열발생 시의 오염원의 확산에 대한 수치모델링을 수행하였다. 모델링 수행 결과를 이용하여 오염원의 이동경로를 예측해보았으며, 다음과 같은 결론을 얻었다. 오염원의 이동방향은 지표면의 지형경사에 따른 흐름과 비슷한 경향을 보이는 것으로 나타났으며, 지하방향으로는 약 8~10m 깊이까지 침투되는 것으로 나타났다. 본 연구를 통하여 장래 하수관거 관리에 효율성을 제공할 것으로 기대된다.

• 한국안전학회지
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• 제29권1호
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• pp.59-63
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• 2014

Smoke is one of the most critical factor when escaping from the fire since it reduces visibility and interrupts finding emergency exit lights. Therefore, it is recommended that an evacuation simulation program should incorporate the smoke factor. In addition, it is suggested that the program should include not only the unilateral damage by the smoke but also the detour evacuation by risk communication. In this study, MAS (Multi Agent System)-based simulation program which incorporates the reduced walking speed by smoke and adopts the dispersion evacuation logic during escaping from the fire. To make comparison, a commercial evacuation program, Pathfinder was used. It was found that the simulation results of MAS (Multi Agent System)-based program is better than Pathfinder in terms of safe evacuation. It means that evacuation simulation need a additional evaluation categories that include not only quick evacuation time but also safe evacuee number.

• 한국재료학회지
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• 제16권10호
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• pp.599-605
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• 2006

N-(3-triethoxysilylpropyl)-1,4-diaminoanthrquinone-2,3-dicarboximide (TESP-DADI), an organic blue pigment, has been prepared and incorporated into silica solid matrix reacting triethyl orthosilicate (TEOS) via sol-gel method. Morphology and microstructure of resulting hybrid pigment were studied employing SEM and TEM. The micrographs and particle size distributions showed that uniform pigment can be obtained employing TEOS-based sol-gel method forming silica core. Particle size distribution of dispersed pigment in water was examined using the technique of dynamic light scattering. The ensuing pigment dispersion ink was subjected to various physicochemical evaluation such as viscosity, surface tension, inkjet stability, storage stability, and color change as inkjet ink using spectrophotometric, and microscopic techniques.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2005년도 추계학술대회 논문집
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• pp.113-115
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• 2005

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2004년도 춘계학술대회 논문집
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• pp.169-170
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• 2004

• Environmental Engineering Research
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• 제7권3호
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• pp.137-148
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• 2002

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2004년도 추계학술대회 논문집
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• pp.193-194
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• 2004

• 한국해안해양공학회지
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• 제3권4호
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• pp.185-196
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• 1991

좌표변환된 측방향 평균 X-Z 수치모형을 수립하여 하구에서 염도확산을 분석하였다. 중력항과 깊이에 따른 밀도변화에 대한 검토와 염도 경계조건의 재평가 등이 이루어 졌으며, 특히 지배방정식중 확산항의 처리에 시간분별방법(fractional step method)을 이용하여 수치해의 안정성 및 간편성을 도모하였다. 개발된 모형을 금강하구에 실제 적용하여 Manning 계수·확산계수 등의 물리적 및 수치적인 특성을 조명하였고, 염도 확산범위를 비롯하여 갈수기의 영향과 대조 및 소조시 염도분포도 파악하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.542-545
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• 2005

This paper is concerned wi th the generation of the Lamb waves in a non­ferromagnetic plate by a recently-developed orientation-adjustable patch-type magnetostrictive transducer (OPMT) and the dispersion analysis from the measured Lamb waves. OPMT is capable of adjusting wave-propagation orientation only with a single installation on a plate. The mechanics behind the wave generation and measurement by the magnetostrictive phenomenon, the working principle of OPMT is explained and the actual generation and measurement of the Lamb waves were conducted in a 3 mm-thick aluminum plate. For the accurate analysis of the dispersion characteristics of the measured Lamb waves, a modified version of the short-time Fourier transform, known as the dispersion-based short-time Fourier transform, was employed. The results presented in this work would serve as the underlying research for an advanced non-destructive evaluation based on ultrasonic waves.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.433-440
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• 2013

We present an experimental and numerical study of spectral profiles of effective group indices of hydrogenated amorphous silicon (a-Si:H) waveguides and of their chromatic-dispersion effect on the four-wave-mixing (FWM) signal generation. The a-Si:H waveguides of 220-nm thickness and three different widths of 400, 450 and 500 nm were fabricated by using the conventional CMOS device processes on a $2-{\mu}m$ thick $SiO_2$ bottom layer deposited on 8-inch Si wafers. Mach-Zehnder interferometers (MZIs) were formed with the a-Si:H waveguides, and used for precise measurement of the effective group indices and thus for determination of the spectral profile of the waveguides' chromatic dispersion. The wavelength ranges for the FWM-signal generation were about 45, 75 and 55 nm for the 400-, 450- and 500-nm-wide waveguides, respectively, at the pump wavelength of 1532 nm. A widest wavelength range for the efficient FWM process was observed with the 450-nm-wide waveguide having a zero-dispersion near the pump wavelength.