• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.257-262
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• 2005

In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.11a
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• pp.33-38
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• 2004

In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.586-590
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• 2009

Recently, an AC Plasma Display Panels(PDP) with the metal sustain electrodes have been reported in order to reduce the manufacturing cost of the AC PDP. However, the luminance and efficacy of the AC PDP with metal electrodes are worse than those of the AC PDP with ITO electrodes. In this paper, various ${\prod}$type metal electrodes are suggested, in order to improve the electro-optical characteristics of the AC PDP with metal electrodes. Among the suggested electrode types, luminance of Hump electrode structure is higher by $40\;cd/m^2$ and discharge current of Asymmetry electrode structure is lower by 5% than those of Pi electrode structure, respectively. Moreover, $T_1$ of Hump electrode structure is reduced to 10% as compared with Pi electrode structure in address period for ADS driving scheme. In all aspects, the characteristics of Hump and Asymmetry electrode structure show best performance.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.701-708
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• 2020

Irradiation of the metal nanoparticles causes local plasmon resonance in a specific wavelength band, which can improve the absorption and scattering properties of a structure. Since noble metal nanoparticles have better resonance effects than those of other metals, it is easy to identify plasmonic reactions and this is advantageous to find the optical tendency. Compared to having a particle gap or randomly arranged particle structures, densely and evenly packed structures can exhibit more uniform optical properties. Using the uniform properties, the structure can be applied to optical filtering applications. Therefore, in this paper, validation tests about metal nanoparticles and thin film structures are conducted for more accurate analysis. The optical properties of monolayer and bilayer noble metal nanoparticle structures with different diameters, packed in a uniform array, are investigated and their optical trends are analyzed. In addition, a thin film structure under identical conditions as metal nanoparticle structure is evaluated to confirm the improved optical characteristics.

• Design & Manufacturing
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• v.2 no.1
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• pp.15-19
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• 2008

While recent industrial structure is various, it is small quantity batch production structure, and products requiring of various functions are increasing. In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.295-299
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• 2006

The inner-structure bonded(ISB) sheet metal is defined as a composite sheet metal which has middle layer of truss-structure between two skin sheets. The characteristics such as ultra-light weight, high rigidity, high strength, etc are required especially for automobile parts. The characteristic of ISB sheet metal depends on inner-structure pattern or method of bonding. Pyramid type of crimped expanded metal is used for inner-structure and both of resistance welding and adhesive bonding are applied to make a specimen. As a result of compression test, it is appeared that forming limit is 10% reduction in thickness under a load of 8kgf per unit element(one inner-structure). In case of uniaxial tensile test the non-uniform surface integrity rather than the buckling of inner-structure happened at a load of 450kgf, which indicates elongation of 7.2% and thickness reduction of 13%. The eye-inspection method was applied to examine the defects occurring on the specimen during stretch forming. In case of biaxial stretch forming only the non-uniform deformation on the surface of a skin sheet could be observed. The forming limit in stretching of ISB sheet metal with the hemi-spherical punch of 150mm in diameter was 3mm in forming depth and 5% reduction in thickness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.660-667
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• 2008

To improve the luminous efficacy of PDPs, an AC PDP with new metal electrode structure is suggested. Operating voltage margin, power consumption, luminance, luminous efficacy, addressing jitter and ICCD image of test panel with proposed structure are measured, to compared with performances of the conventional ITO structure and proposed structures. To enhance luminous efficacy, we designed new structure which have asymmetric metal electrode structure. The experimental results show that the suggested structure shows luminance to maximum 89% and luminous efficacy to maximum 107% compared with conventional ITO standard structure. In addition, proposed structures with asymmetric electrode show low power consumption by $2{\sim}3%$, high luminance by $5{\sim}7%$, and high luminous efficacy by $2{\sim}3%$ compared with proposed symmetric electrode structures.

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.27-32
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• 2011

This study has numerically investigated the flame structure and emission characteristics in the metal fiber burner. The one-dimensional premixed flame approach has been adopted to simulate the combustion processes of the metal fiber burner. Numerical results indicate that the present approach is capable of predicting the essential combustion characteristics of the metal fiber burner. Based on numerical results, the detailed discussion has been made for the effects of equivalence ratio and thermal load on the precise flame structure and the pollutant emission in the metal fiber burner.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.448-453
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• 2010

Porous media containing complex fluid passage have especially large surface area per unit volume. This study is aimed to identify the heat transfer characteristics of high-porosity metal foams in a horizontal channel. Experiment is performed under various heat flux, velocity and pore density. Nusselt number decreases with higher pore density. Metal foams shows higher heat transfer coefficients than pin-fin structure with the same porosity. This is due to the more complex flow passage and larger heat transfer area based on the structure of the metal foams. The analysis on the pin-fin structure may not be suitable to the metal foam structure but should be identified extensively through further study.

• Bulletin of the Korean Chemical Society
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• v.17 no.1
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• pp.43-45
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• 1996

Structural and electronic properties of an alkali metal fulleride, Rb1C60, was studied. In spite of the chain structure with shortdistance between balls along the crystallographic a-direction, the electronic structure calculation study with the X-ray defined crystal structure shows that Rb1C60 is a three-dimensional metal at room temperature. This result is different from the magnetic experiments in which the compound was found to behave as a quasi-one-dimensional metal. Partial Fermi surface nesting is supposed to be the reason for the metal-insulator transition found in Rb1C60 at ∼50 K.