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1.
Yong-Seog?SeoEmail author Kwang-Sup?Song Sung-Kyu?Kang 《Korean Journal of Chemical Engineering》2003,20(5):819-828
A numerical investigation of a catalytically stabilized thermal (CST) combustor was conducted for a multichannel catalyst
bed, and both the catalyst bed and thermal combustor were simultaneously modeled. The numerical model handled the coupling
of the surface and gas reaction in the catalyst bed as well as the gas reaction in the thermal combustor. The behavior of
the catalyst bed was investigated at a variety of operating conditions, and location of the flame in the CST combustor was
investigated via an analysis of the distribution of CO concentration. Through parametric analyses of the flame position, it
was possible to derive a criterion to determine whether the flame is present in the catalyst bed or the thermal combustor
for a given inlet condition. The results showed that the maximum inlet temperature at which the flame is located in the thermal
combustor increased with increasing inlet velocity. 相似文献
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Hydrogen control in the case of severe accidents has been required by nuclear regulations to ensure the integrity of containment after TMI accidents. Up to now, many experiments have been conducted to estimate the distribution of hydrogen during accidents in nuclear power plants. In this article, we proposed a computer code named HYCA3D developed to calculate the local hydrogen distribution with three-dimensional time-dependent governing equations, which can simulate the transport of multiple species. Also, local hydrogen behavior has been experimentally investigated in a cylindrical multi-subcompartment mixing chamber, measuring the local concentration in various conditions. Hydrogen is simulated by helium in the experiments. The proposed code was verified with these experimental results, followed by pre-tests with EPRI/HEDL standard problems. The calculation results show good agreement with the experimental data. 相似文献
4.
Jong-Hwan Park Jong-Hyun Lee Yong-Ho Lee Yong-Seog Kim 《Journal of Electronic Materials》2002,31(11):1175-1180
The reaction characteristics of molten Au/Sn eutectic solder with potential diffusion-barrier materials of optoelectronic
packages were investigated. The characteristics were studied by reflowing the solder on Pt, Ni, and Co plates, respectively,
and by measuring the thickness of the reaction product. In addition, the dissolution rate of Pt into the solder was measured.
The results indicated that Pt, which is commonly used as the diffusion-barrier layer in the under-bump metallurgy (UBM) of
optoelectronic packages, reacts readily with the molten solder, resulting in discontinuous reaction products at the solder/Pt
interface. Cobalt, on the other hand, reacted with the solder at an order of magnitude slower rate than that of Pt and provided
an effective barrier against the reaction with the solder. 相似文献
5.
Anisotropic self-alignment of the noncircular pads is investigated to reduce the misalignment in electronic packaging, and
the effects of the direction and length ratio of the noncircular pads are analyzed. The restoring forces of circular and noncircular
pads are calculated numerically using the surface evolver and are compared with the experimental data. The restoring force
in the minor-axis direction of the noncircular pad becomes largest followed by the circular pad and the major-axis direction
of the noncircular pad. Directionality increases with the length ratio, which implies that more accurate alignment can be
achieved in the specific direction. 相似文献
6.
Physical Properties of Barrier Ribs of Plasma Display Panels: II, Effects of Fillers 总被引:1,自引:0,他引:1
Geon-Ho Hwang Won-Yong Kim Hyung-Jo Jeon Yong-Seog Kim 《Journal of the American Ceramic Society》2002,85(12):2961-2964
The effects of inert fillers, such as quartz and Al2 O3 , on the sintering behavior and physical properties of lead borosilicate glasses used for barrier ribs of plasma display panels (PDP) were investigated. The effects of volume fraction and type of filler on the sintering temperature, thermal expansion coefficient, dielectric constant, and fracture resistance of the barrier ribs of PDP were investigated. The influence of the filler on sintering behavior was discussed based on the wetting angle of the glass on the fillers. The physical properties and fracture resistance of the glass with fillers were measured and compared with theoretical models. 相似文献
7.
Yong-Seog Seo Sang-Pil Yu Sung-June Cho Kwang-Sup Song 《Chemical engineering science》2003,58(1):43-53
The characteristics of a catalytic heat exchanger which integrates heat generation and heat exchange into one equipment have been investigated by the experiment and numerical simulation. The surface of the fin tubes was catalyzed by the formation of the oxide layer and the subsequent washcoating of ZrO2, followed by the impregnation of Pd catalyst. The experimental results showed that the performance of catalytic combustion in the catalytic heat exchanger was more significantly affected by the inlet velocity of the mixture than by its inlet temperature and equivalence ratio. It was also found that the catalytic surface area was a critical parameter to obtain the complete conversion of the mixture. Numerical simulation has been performed with a commercial software FLUENT. The calculated results indicated that the performance of the catalytic combustion was influenced by the catalytic fin configuration as well as the flow pattern of the mixture over the catalytic fins. The results recommend that the number and thickness of catalytic fins should be designed above 6 pieces/inch and less than to achieve the best performance in the catalytic heat exchanger. 相似文献
8.
Yong-Seog Kim Seog-Young Lee Soon-Kug Hong Hyung-Jo Jeon 《Journal of the American Ceramic Society》2001,84(7):1470-1474
In an attempt to explore the possibility of forming barrier ribs for a plasma display panel by plastically deforming a green tape with a grooved roll, the effects of green tape composition and rolling parameters on the height of the barrier ribs formed were studied. For the analysis of the results, viscosity of the green tape was evaluated using a modified slit rheometer. The results indicated that the effects of organic constituents in the green tape and processing parameters on the dimension of the barrier ribs formed are closely related with the pseudoplastic characteristics of the green tape. 相似文献
9.
Sang-Pil?YuEmail author Yong-Seog?Seo Kwang-Sup?Song Sung-June?Cho Nam-Joe?Jeong Ihn-Su?Ryu Sung-Kyu?Kang 《Korean Journal of Chemical Engineering》2003,20(3):457-460
Catalytic combustion is thought to be a considerable improvement on the traditional one under specific conditions. Due to
its special features, catalytic combustion has two strong points compared to flame: no NOx emission and high reaction efficiency. However, the preheating process of catalytic combustion is an obstacle that deteriorates
profitability in operation. So the HTHE (High Temperature Heat Exchanger) is adapted to the system to reinforce the preheating
process, and we show that the catalytic combustion is maintained steadily without exceptional heat injection. As a result,
the stability on the catalytic surface is the most important operational factor. To achieve it, both mixture gas property
and temperature distribution should be controlled. 相似文献
10.
Self-Propagating High-Temperature Synthesis of Aluminum Nitride under Lower Nitrogen Pressures 总被引:4,自引:0,他引:4
Jason Shin Do-Hwan Ahn Mee-Shik Shin Yong-Seog Kim 《Journal of the American Ceramic Society》2000,83(5):1021-1028
The synthesis of aluminum nitride (AlN) via self-propagating high-temperature synthesis (SHS) was attempted, using aluminum powder that was mixed with AlN powder as a diluent. The AlN content in the reactant was varied over a range of 30%–70%, and the nitrogen pressure was varied over a range of 0.1–1.0 MPa. The SHS reaction that was performed using a reactant that contained 50% AlN diluent, under a nitrogen-gas pressure of 0.8 MPa, yielded the highest conversion ratio of aluminum powder to AlN powder. A mechanism for the reaction of aluminum with nitrogen gas during the SHS process was discussed, based on observations of the microstructures of the reaction zone and products. 相似文献