• 환경영향평가
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• 제26권4호
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• pp.242-256
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• 2017

본 연구에서는 위험물질 누출 사고로 인한 영향을 예측하고 피해를 줄이기 위한 대응 방안으로 기상장(풍향 풍속)과 실제 도시 구조를 고려한 가상의 사고 시나리오를 구축하였다. 위험물질 확산에 대한 시나리오를 기반으로 서울시 강남 지역을 대상으로 보행자 환경에서의 위험특성을 분석하였다. 풍향과 풍속 조건에 따라 48개의 시나리오를 가정하였으며, 스칼라 물질의 확산 특성을 분석하기 위한 위험물질로써 불화수소를 가정하였다. CFD_NIMR_SNU 모델을 이용하여 모의한 기상장(풍향 풍속) 평가를 실시하여 모든 검증 지수가 유효한 범위 내에 나타남을 보였다. 보행자 고도에서 모의된 확산장 분석 결과, 도시의 인공적 구조에 의해 기상장의 조건에 따라 상세 흐름이 변화하며 위험물질이 확산되는 경향에 영향을 미치는 것을 확인하였다. 또한, 유입류의 풍속이 가장 약한 조건의 경우, 하층에서 유입방향의 역방향으로 흐름이 형성되어 보행자 고도에서의 물질 이동경로가 변화함을 보였다. 본 연구에서는 도시 지역의 난류흐름 형성에 도시의 인공적 구조가 매우 중요한 영향을 미치는 것을 보였다. 본 연구에 사용된 기술은 향후 실제 위험물질을 취급하는 도시 내 산업단지에 확산모의 실험과 보행자 환경에서의 위험성 평가에 유용할 것으로 기대된다.

• 한국해안·해양공학회논문집
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• 제27권2호
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• pp.79-93
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• 2015

Gulf Stream 인근해역에서 해양 중규모 와동의 삼차원 구조분석을 HYCOM 수치모델을 사용하여 수행하였다. 시계방향 및 반시계 방향으로 회전하는 와동들의 구조를$1/12^{\circ}$와 $1/48^{\circ}$ 두개의 모델 해상도를 사용하여 비교하였다. 라그랑지안 모수인 Finite Size Lyapunov Exponent (FSLE) 와 Okubo-Weiss parameter(OW) 분포를 분석한 결과 표층의 와동구조가 수심 깊은 곳까지 영향을 미치는 것으로 나타났는데, 이는 와동에 의한 수평방향 해수운동이 수직방향 해수운동보다 크기 때문인 것으로 해석되었다. 고해상도 모델의 경우 와동근처에서 10 km 미만의 미세난류구조 들이 많이 발견되었으며, 이러한 미세난류구조들은 고해상도 모델의 와동근처에서 해수의 움직임을 저해상도 모델보다 불규칙하게 만드는 것으로 나타났다. 이러한 미세난류구조에 의한 해수의 불규칙한 움직임은 분산계수 (dispersion coefficient)에도 영향을 미치는데, 수평 분산계수의 경우 해수운동이 자유로운 고해상도 모델이 저해상도 모델보다 그 값이 더 크게 나타났다. 수직 분산계수의 값은 저해상도 모델에서 더 크게 나왔는데, 이는 와동의 경사진 궤도를 따라 움직이는 저해상도 모델의 해수운동이 수직 분산계수값을 증가시키기 때문인 것으로 들어났다. 상대 수직 분산계수의 경우 이러한 궤도의 영향이 줄어들기 때문에 해수의 수직운동을 측정하는데 있어 절대 수직 분산계수 보다 더 적합한 것으로 판명되었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.698-700
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• 2003

LGP (Light-Guide Panel) of TFT-LCD Backligh/Frontlight is one of the major components which affect on the product quality of LCD. Since the brightness distribution of LGP is sensitive to the process error in manufacturing, the optical characteristics such as reflection and absorption of LGP pattern should be modeled including the process error. LGP is developed by using the fast and reliable design technology, which uses the concept of the inverse-design, makes the model on the characteristics of uncertainty in the manufacturing process, and designs the dispersion pattern analytically without try-and-error by using an artificial intelligence. The PEA(Process-Error-Adaptive) design gives the best solution in handling the process error. The offset of target in feedback system makes such the best pattern design possible that the brightness distribution is nearly same (more than 90%) with target in regardless of the miscellaneous errors in mass production. The present design method has been also applied to frontlight and multi-side-lamp(eg., four-side-four-lamp) backlight.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.295-298
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• 1997

Recycl ing of PP/EPR based bumper coated with polyester urethane paint has been per formed by chemical decoating method. Electronic Speckle Pattern Interferometry (ESP11 has been applied to characterize the deformation of polyolef in based bumper. In additon, physical properties and processability of recycled materials have been investigated by dynamic mechanical thermal analysis, impact test and melt flower index measurement. The results show that the deformation ratio of recycled material is higher than that of virgin one. The morphological change of EPR, degree of distribution and dispersion during the recycling process seem to be the most important factor for the deformation and the mechanical properties of recycled materials. The experimental results obtained show that ESPI is very powerful technique to study the thermal mechanical property of polyolefin bumper system.

• 대한교통학회지
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• 제6권1호
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• pp.55-64
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• 1988

Prior to using any computer model, the program-embedded palameters showing significant differences from real world should be calibrated. This is especially true when the model is expected to be used fro various roadway and traffic condition. The calibration of TRANSYT model was conducted for the parameters of start-up delay, and lag, stop penalty(K), platoon dispersion factor, and saturation flow rate. The values of the parameters were obtained by theoretical methods from actual field measurements for discharging and arrival pattern. The sites elected for the study was an intersection of Dongil-Ro and Hwarang-Ro, and a 334 meter downstrean section from the intersection stop line on westbound Hwarang-Ro. The study results showed that the start-up delay was 2.6 sec, end lag was 1.0 sec, saturation flow rate was 2287 pcphgpl, platoon dispersion factor was 0.2-03, and stop penalty(K) was 32. However, since these parameters re apt to depend on traffic and roadway condition, it is doubtful whether the obtained values will be applicable to the area-wide situation other than this particular site.

• Preventive Nutrition and Food Science
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• 제3권3호
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• pp.292-294
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• 1998

Surimi sol and gel were prepared by mixing egg albumin, starch, oil and carrageenan, which are used as representative ingredients in the surimi composite, at different ratio. Structural properties in surimi composite were investigated by examining the phase changes and dispersion pattern (average particle size, size range and the averge number of particle) of the particulate ingredients in sol and gel with an image analyzer. A staining technique of the specimen containing egg albumin in surimi gel was developed by adjusting pH of a toluidine staining solution. Image analysis revealed that size and density of ingredient particles were function of the level and dispersion of ingredients except of starch-incorporated surimi gel which showed maximum particle size at 6%.

• 설비공학논문집
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• 제23권5호
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• pp.349-355
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• 2011

In this study, numerical simulation has been conducted to investigate dispersion of a pollutant released from a new furniture, a kind of Sick Building Syndrome (SBS). A sofa which generates formaldehyde is implemented by using an immersed boundary method. Large Eddy Simulation (LES) is employed to obtain time-dependent velocity and concentration fields. It is shown that the ventilation efficiency in this room can be improved by changing inlet angle of diffuser, even though other conditions still remain unchanged. Both active diffusion near a sofa and air flow pattern are important parameters to enhance the ventilation efficiency.

• 한국대기환경학회지
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• 제18권5호
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• pp.393-400
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• 2002

Separation distance between industrial source and residential areas to avoid odor annoyance was investigated using AUSPLUME model. A Gaussian plume model (AUSPLUME) for the dispersion was used to calculate odor emission from ground level area source. Using the dispersion model to calculate ambient odor concentrations, the separation distance between industrial source and residental areas was defined by %HA (percentage of highly annoyed person) and odor percentile concentration (C98). The result was compared with the separation distance of various nation guidelines for livestock buildings. The calculated separation distance for industrial source showed similar pattern comparing with various guidelines for livestock buildings.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.555-559
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• 2015

Coherence length (time) is a key parameter in many classical and quantum optical applications. Two interferometers – Michelson and Young’s double-slit – are used to characterize the temporal coherence of single photons emitted from single terrylene molecules. For quantitative analysis, a dispersion-related distortion in the interference pattern of a Michelson interferometer is carefully corrected by a simple dispersion compensation. Additionally, it has been demonstrated that Young’s interferometer can be used in temporal coherence studies at the single photon level with high accuracy. The pros and cons of the two systems are discussed. The measured coherence lengths in the two systems are consistent with one another under the self-interference interpretations.

• Macromolecular Research
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• 제14권3호
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• pp.312-317
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• 2006

In the preparation of a polyacrylonitrile (PAN)/sodium montmorillonite (Na-MMT) nanocomposite via an in-situ polymerization method, macroazoinitiator (MAI) was intercalated in the gallery of Na-MMT to enhance the delamination of silicate layers by intergallery polymerization. The exfoliated fine dispersion observed by X-ray diffraction pattern and transmission electron microscopy, the enhanced tensile storage modulus and the thermal decomposition temperature showed that the intercalated MAI was effective in inducing intergallery polymerization and that a poly(ethylene glycol) block linked to a PAN block improved the dispersion of hydrophilic Na-MMT in the polymer matrix.