• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.563-568
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• 2003

Recently, the recycled amount of electric, mechanical parts, and appliances in artifacts has increased. These products use valuable rare metals such as platinum group metals and gold, which are included occasionally as additives. Rare metals are maldistributed in the world and most of them are produced in small quantities. A small amount of rare metals used in the appliances causes a large loss of rare metal resources because of the lack of an economically recycling method. The present recycling technologies including physical and chemical separation methods that are considered for recycling of electric, mechanical parts and appliances.

• Earthquakes and Structures
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• 제7권6호
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• pp.1093-1118
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• 2014

A sophisticated story-wise stiffness identification method for a shear building structure is applied to the case where the shear building is subjected to an actual micro-tremor. While the building responses to earthquake ground motions are necessary in the previous method, it is shown that micro-tremors can be used for identification within the same framework. This enhances the extended usability and practicality of the previously proposed identification method. The difficulty arising in the limit manipulation at zero frequency in the previous method is overcome by introducing an ARX model. The weakness of small SN ratios in the low frequency range is avoided by using the ARX model together with filtering and introducing new constraints on the ARX parameters.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.638-643
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• 2009

A computer-generated hologram(CGH) is made for three-dimensional image reconstruction of a virtual object which is a difficult to irradiate the laser light directly. One of the adverse effect factors is quantization of wave front computed by program when a computer-generated hologram is made. Amplitude element is not considered in Kinoform, it needs processing to reduce noise or false image. So several investigation was reported that the improvement of reconstructed image of Kinoform. Means to calculate the most suitable complex amplitude distribution are iterative algorithm, simulated annealing algorithm and genetic Algorithm. Error diffusion method reconstructed to separate the object as for the noise that originated in the quantization error. So it is efficient method to obtain high quality image with not many processing.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.682-683
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• 2006

Thermoelectric conversion efficiency of thermoelectric elements can be increased by using a structure combining n-type and p-type semiconductors. From the above point of view, attention was directed at ZnO as a candidate n-type semiconductor material and investigations were made. As the result, a dimensionless figure of merit ZT close to 0.28 (1073K) was obtained for specimens produced by the PCS (Pulse Current Sintering) method with addition of specified quantities of $TiO_2$, CoO, and $Al_2O_3$ to ZnO. It was found that the interstitial $TiO_2$ in the ZnO restrains the grain growth and CoO acts onto the bond between grains. The influence of the inclusion of $TiO_2$ and CoO onto the sintering behavior also was investigated.

• 한국수자원학회논문집
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• 제33권S1호
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• pp.101-110
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• 2000

This paper introduces the equivalent frequency response method(EFRM) into runoff analysis. This EFRM originally had been developed to analyze dynamic behavior of nonlinear elements such as threshold and saturation in control engineering. Many runoff models are described by nonlinear ordinary of partial differential equations This paper presents that these nonlinear differential equations can be converted into semi-linear ones based on EFRM. The word of "a semi-linear equation" means that the coefficients of derived equations depend on average rainfall.

• International Journal of Aerospace System Engineering
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• 제2권1호
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• pp.47-52
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• 2015

The transient phenomenon of self-powered energy-harvesting is assessed using a bond-graph method. The bond-graph is an energy-based approach to describing physical-dynamic systems. It shows power flow graphically, which helps us understand the behavior of complicated systems in simple terms. Because energy-harvesting involves conversion of power in mechanical form to the electrical one, the bond-graph is a good tool to analyze this power flow. Although the bond-graph method can be used to calculate the dynamics of combining mechanical and electrical systems simultaneously, it has not been used for harvesting analysis. We demonstrate the usability and versatility of bond-graph for not only steady analysis but also transient analysis of harvesting.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2000년도 학술발표회 논문집
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• pp.1-2
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• 2000

This paper introduces the equivalent frequency response method (EFRM) into runoff analysis. This EFRM originally had been developed to analyze dynamic behavior of nonlinear elements such as threshold and saturation in control engineering. Many runoff models are described by nonlinear ordinary or partial differential equations. This paper presents that these nonlinear differential equations can be converted into semi-linear ones based on EFRM. The word of “a semi-linear equation” means that the coefficients of derived equations depend on average rainfall

• 한국결정성장학회지
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• 제9권6호
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• pp.535-541
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• 1999

Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si doped GaAs crystals for photonic devices, and low-dislocation-density low-residual-strain 4-inch to 6-inch semi-insulating GaAs crystals for electronic devices by Vertical Bridgman(VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.349-352
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• 1988

A problem of the surface friction is inevitable in the micro machines. However, the levitation by Meissner effect of high Tc superconductor gives a complete solution to the problem. The repulsive force between permanent magnets and superconductors is utilized to levitate and actuate micro structures without the surface friction. In this paper, a micro actuator using; Meissner effect of high Tc superconducting film (Meissnac) is proposed ; Meissnac is drived by the control of (Sugerconducting/ Normal) states of superconductor. The levitating force and the driving force are analyzed by the numerical method.

• 상하수도학회지
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• 제9권3호
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• pp.78-87
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• 1995

A study on the fouling control by periodical ozone-scrubbing was conducted in a membrane filtration process for drinking water treatment. Hydrophilic hollow fiber polyethylene membrane with pore size of $0.1{\mu}m$ and its surface area of $0.42m^2$ was used. Dead-End filtration method was selected to obtain high efficiency of energy. Laboratory prepared synthetic raw water with kaolin was used and the membranes were scrubbed by ozone once in an hour and once in two hours. When the duration of ozone scrubbing was increased from 10 seconds to 20 seconds, the rate of membrane fouling was significantly decreased. Although the frequency of ozone-scrubbing was reduced from once in an hour to once in two hours. the effect of fouling control was unchanged. However, ozone-scrubbing was not effective after a membrane was fouled and washed with detergent for reuse. Among several possible working effects of ozone, bactericidal effect was confirmed to be the primary reason of fouling control.