• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.354-356
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• 2008

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.24.2-24.2
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• 2005

• The Science & Technology
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• v.28 no.8 s.315
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• pp.80-81
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• 1995

알파입자비적밀도 이론계산방법에 관한 개발연구로 우리나라 원자력 발전에 큰 공을 세운 윤석철 박사. 윤박사는 "우리나라와 같이 국토가 좁고 인구가 조밀한 지역에서는 원자력산업을 추진함에 있어 환경과 잘 조화를 이룰 수 있는 방사선 안전문화를 정착시키기 위한 보건물리 기술개발이 필요적" 이라고 강조한다.

• Proceedings of the KSEEG Conference
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• 2001.04a
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• pp.390-392
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• 2001

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.813-818
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• 1998

Ultrafine powders of $\textrm{In}_{2}\textrm{O}_{3}$-doped $\textrm{SnO}_{2}$ were synthesized by a coprecipitation method and the effects of pH value and the amount of In2Q addition on particle size were investigated. The influence of pH value on particle size could be negligible, whereas the amount of $\textrm{In}_{2}\textrm{O}_{3}$ has influenced on particle size and specific surface area. The gas sensitivity to hydrocarbOn($\textrm{C}_{3}\textrm{H}_{8}$, $\textrm{C}_{4}\textrm{H}_{10}$) increased with $\textrm{In}_{2}\textrm{O}_{3}$ addition and reached a maximum at 3wt.% addition. From the results of impedance analysis and I-V characteristics. it was showed that the agglomeration structure of particles and the boundaries between agglomerates were the important factors to determine the gas sensing mechanism.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.219-224
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• 2020

Industrial mixers to homogeneously blend particulate materials have been developed and widely used in various industries. However, most industrial mixers have at most two-degree-of-freedom for the operation, which limits the range of operation parameter selection for optimal blending. This paper proposes a multi-degree-of-freedom robotic mixer designed by converging a conventional drum blender and a robotic manipulator and evaluated its performance in a virtual operating environment. Discrete element simulations were conducted for mixing performance evaluation. The numerical results showed that the proposed mixer design exhibits a better mixing performance than conventional ones.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.1
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• pp.26-33
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• 2017

In this study, the surface marker method, one of the particle tracking methods, used to track the free surface is extended to cover the more general cases easily including the collision and separation of the free surface. In surface particle method to redistribute particles effectively using the grid system, the free surface is composed of the sum of quadrilaterals having four curves where fixed markers are placed at ends of each curve. Fixed markers are used to know how curves are connected to each other. The position of fixed markers can move as the free surface deforms but all fixed markers cannot be deleted during all time of simulation to keep informations of curve connection. In the case of the collision or separtion of the free surface where several curves can be intersected disorderly, severe difficulties can occur to define newly states of curve connection. In this study, the adaptable surface parTicle method without fixed markers is introduced. Intersection markers instead of the fixed markers are used to define quadrilaterals. The position of the intersection markers is defined to be the intersection point between the free surface and the edge of the grid and it can be added or deleted during the time of simulation to allow more flexibilities. To verify numerical schemes, two flow cases are simulated and the numerical results are compared with other's one and shown to be valid.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.208-208
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• 2009

메탄의 수증기-이산화탄소 복합개질반응에서 니켈 촉매의 탄소 침적 저항성에대한 Ce 증진 효과를 살펴보기 위해, Ni-Ce/${\alpha}-Al_2O_3$ 촉매를 제조하였다. Ce/Ni 비율 변화에 따른 촉매 비표면적, Ni 입자 분산도 및 촉매 활성 변화를 살펴보았고, Ce 첨가량을 최적화 할 수 있었다. Ce/Ni 비율 증가에 따라 NiO 결정크기가 감소하고 표면적과 Ni 분산도는 증가하였다. 특히, Ce/Ni=0.5 첨가 시, 촉매는 가장 넓은 비표면적과 Ni 분산도를 가졌으며, 우수한 촉매 활성 및 높은 탄소 침적 저항성을 보였다. 또한, 본 연구에서는 Ni과 Ce 담지 방법에 따른 Ni 분산도 향상과 Ni과 Ce간의 접촉 면적 극대화를 통한 활성산소 공급 향상에 대한 영향을 함께 살펴보았다. Ni과 Ce를 동시 함침법과 연속 함침법으로 담지하여 비교한 결과, 동시 함침법으로 제조한 Ni-Ce/${\alpha}-Al_2O_3$ (Ce/Ni=0.5) 촉매가 가장 우수한 촉매 성능 및 높은 탄소 침적 저항성을 보였다. 이는 동시 함침법으로 고분산된 Ni 입자와 담체간의 강한 상호작용 형성과 원활한 활성 산소 공급에 기인한 것이다.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.201-206
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• 2019

The flooding and overtopping due to unexpected large ocean wave may occur serious problems to environments and structures. Generally fixed wave breakers and several structures were installed to prevent such damages, however, they may affect to environments and charted path of ships badly. In this regard, new type of initial wave breaker was investigated in both of experimentally and numerically. For the experiments, conceptual devices were built by authors with stereo vision system. The moving particle semi-implicit method was adopted for simulation. It is revealed that the initial wave breaker reduce the damages from ocean waves by energy dissipated earlier. Furthermore, the effects of position of the initial wave breaker was also considered.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.577-581
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• 2011

Silicon nanoparticles have attracted a great deal of scientific interests due to its intense photoluminescence in the visible spectral region and its potential applications in biological fluorescence maker, RGB (red, green, blue) display, photonics and photovoltaics etc. Practical applications making use of optical and physicochemical properties of Si nanoparticles requires an efficient synthetic method which allows easy modulation of their size, size distribution as well as surface functionalities etc. In this study, a one-pot solution reduction scheme is attempted to prepare alkyl-terminated Si nanoparticles (<10 nm) with Si precursors, (Octyl)$SiCl_3$ or mixture of (Octyl)$SiCl_3$ and $SiCl_4$, containing alkyl-groups using Na(naphthalide) as reducing agent. The surface capping of Si nanoparticles with octyl-groups as well as Si nanoparticle formation was achieved in one-pot reaction. The hexane soluble Si nanoparticles with octyl-termination were in the range of 2-10 nm by TEM and some oxide groups (Si-O-Si) was present on the surface by EDS/FTIR analyses. The optical properties of Si nanoparticles measured by UV-vis and PL evidenced that photoluminescent Si nanoparticles with alkyl-termination was successfully synthesized by solution reduction of alkyl-containing Si precursors in one-pot reaction.