• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.473-480
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• 2011

Recently, the resizing algorithms based on the displacement participation factors have been developed for sizing members to satisfy stiffness criteria. It is proved that this resizing algorithms made for utilizing worker's stiffness design are practical and rational due to the simplicity and convenience of the method. The resizing algorithm can be practically and effectively applied to drift design of buildings. However, the researches on the change of inelastic behavior by the resizing algorithm has been insufficient. To identify the effect on the inelastic behavior of buildings by the resizing method, this study used the reinforced concrete shear wall-frame example. Through the application of the resizing method, the weights of shear wall in the lower class and the weights of columns and beams in the upper class increased respectively. And the initial stiffness of the building increased and the ductility of the buildings had similar with that of the initial structure.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.33-43
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• 2011

In this study, simplified analysis (discrete analysis of column and pile) of pile bent structures was performed on the basis of the equivalent base spring model. And the minimum reinforcement ratio in pile bent structures was evaluated by taking into account various factors. To obtain the detailed information, simplified analysis was performed for column-pile interactions and the behavior of a column-pile was estimated and highlighted. Based on this study, it is shown that previous design method based on virtual fixed point theory cannot adequately predict the physical behavior of pile bent structures. It is found that the maximum bending moment is located within craking moment of the pile when material non-linearity is considered. It is also found that the minimum reinforcement ratio (=0.4%) is appropriately applicable for the optimal design of pile bent structure under ultimate lateral loading.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.678-687
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• 2012

Concentration fields of solid powder in a liquid fuel were quantitatively measured by a visualization technique. The measurement system consists of a camcoder and three LCD monitors. The solid powder (glass powder) were filled in a head tank which was installed over a main mixing tank ($D{\times}H$, $310{\times}370mm$). The main mixing tank was filled with JetA1 fuel oil. With a sudden opening of the upper tank by pressurized nitrogen gas with 1.9 bar, the solid powder were poured into the JetA1 oil. An impeller type agitator was being rotated in the mixing with 700 rpm for the enhancements of mixing. Uniform visualization for the mixing flow field was made by the light from the three LCD monitors, and the visualized images were captured by the camcoder. The color images captured by the camcoder The color information of the captured images was decoded into three principle colors R, G, and B to get quantitattive relations between the concentrations of the solid powder and the colors. To get better fitting for the strong non-linearity between the concentration and the color, a neural network which has strong fitting performances was used. Analyses on the transient mixing of the solid powders were quantitatively made.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.57-65
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• 2002

In this paper, a 2.5V 10-bit 300MSPS CMOS D/A Converter is described. The architecture of the D/A Converter is based on a current steering 8+2 segmented type, which reduces non-linearity error and other secondary effects. In order to achieve a high performance D/A Converter, a novel current cell with a low spurious deglitchnig circuit and a novel inverse thermomeer decoder are proposed. To verify the performance, it is integrated with $0.25{\mu}m$ CMOS 1-poly 5-metal technology. The effective chip area is $1.56mm^2$ and power consumption is about 84mW at 2.5V power supply. The simulation and experimental results show that the glitch energy is 0.9pVsec at fs=100MHz, 15pVsec at fs=300MHz in worst case, respectively. Further, both of INL and DNL are within ${\pm}$1.5LSB, and the SFDR is about 45dB when sampling, frequency, is 300MHz and output frequency is 1MHz.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1131-1136
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• 2014

Recently, power converters installed on the specialized vessels such as LNG Carrier and Icebreaker and offshore plants mainly use diode rectifier. However, such devices cause distortion of supply voltage waveform by involving much harmonics to input current of non linearity load in rectifying operation. Distortion of supply voltage waveform can be problems such as false operation of generator, transformer and load device and deterioration of power quality. This thesis is focusing with a view to producing accurate sinusoidal AC waveform with certain load through improvement of distortion of current waveform causing under operation of rectifier by using accurate circuit of DC shaping. The result of computer simulation proved that harmonics involved in current and voltage waveform of power system can be reduced.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.558-563
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• 2008

Vibration/shock affects biggest taking a train subtraction of vehicle and durability decline. Therefore, absorber is used for vibration/shock isolation and various qualities of the material and design are applied to isolation. This paper proposes vibration/shock absorber that applies 'Disc' spring. Through comparison with 'Disc' spring that has nonlinearity and coil spring that is having linearity, see effect that nonlinearity of isolation gets in vibration/shock Isolation. Coil spring and 'Disc' spring are non-linear numerical analysis and simulation through theory for this, get and investigate comparison result through an experiment finally. Expressed and formulated shock through 'Runge-Kutta' method/impact response to nonlinear-vibration-equation of 1 degree of freedom for numerical analysis. Double half sine pulse of excitation used and analyzed result through spectrum response analysis here. Response of disc spring is compared to response of coil spring by changing $h_o/t$ ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and to design the optimal absorber under the limited condition. And then, the isolation effect was analyzed through the shock test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.990-993
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• 2008

Vibration/shock affects biggest taking a train subtraction of vehicle and durability decline. Therefore, absorber is used for vibration/shock isolation and various qualities of the material and design are applied to isolation. This paper proposes vibration/shock absorber that applies 'Disc'spring. Through comparison with 'Disc' spring that has nonlinearity and coil spring that is having linearity, see effect that nonlinearity of isolation gets in vibration/shock isolation. Coil spring and 'Disc' spring are non-linear numerical analysis and simulation through theory for this, get and investigate comparison result through an experiment finally. Expressed and formulated shock through 'Runge-Kutta' method/impact response to nonlinear-vibration-equation of 1 degree of freedom for numerical analysis. Double half sine pulse of excitation used and analyzed result through spectrum response analysis here. Response of disc spring is compared to response of coil spring by changing ho/t ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and to design the optimal absorber under the limited condition. And then, the isolation effect was analyzed through the shock test.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4215-4220
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• 2011

This study introduces a new concept for a simple, efficient and cheap sensitivity amplification of a Quartz Crystal Microbalance (QCM) based immunosensor system for the detection of tumor necrosis factor-alpha (TNF-${\alpha}$, TNF) by using an in-built magnetic system. The frequency shift due to the applied magnetic field was successfully observed on magnetic particles labeled detection antibodies, anti-human TNF-${\alpha}$, which were bound to the immunologically captured TNF-${\alpha}$ on the gold coated quartz crystals. In the present system, the magnitude of frequency shift depends on both the strength of magnetic field and the amount of target antigen applied. Significant signal amplification was observed when the additional built-in residual stress generated by the modified magnetic particles under the magnetic field applied. Used in conjunction with a sandwich type non-competitive immunoassay format, the lower detection limit was calculated to be 25 $ngmL^{-1}$ and showed good linearity up to TNF-${\alpha}$ concentrations as high as 2.0 ${\mu}gmL^{-1}$. The sensitivity, most importantly, was improved up to 4.3 times compared with the same QCM system which was used only an antigen-antibody binding without additional magnetic amplification.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.265-272
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• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Geotechnical Engineering
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• v.14 no.5
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• pp.191-204
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• 1998

The feasibility of fly ash was evaluated as an alternative liner material to the conventional clay liner of landfills through modeling and laboratory experiments. In order to consider the effect of unsaturation on water flow through the liner, analyses were made to compare flow characteristics in saturated liner with that of unsaturated one. Contaminant migration characteristics in liners were investigated by batch experiment and modeling, in which phenol was employed as a model was solved by numerical techniques of finite difference method and predictor-corrector method to deal with high non-linearity. Sequential method was used to handle the system of differential equations. Results show that the alternative liner material is more capable of cutting off water flow in unsaturated condition and in preventing phenol from passing through it. It can be seen that, under the flow conditions considered in this study, the conventional saturation approach underestimates the amount of water passing through the liner and doers the cut-off capability against phenol significantly.