• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.10
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• pp.53-59
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• 1997

In this paper, we present a 20 GHz low-loss dual-mode channel filter designed by using mode matching method. The performance of dual-mode channel filter mainly depends on iris characteristics. Therefore the exact design of iris is the key point to get good frequncy response of the filter. MOde matching technique is widely used ot design several kinds of waveguide filters because it is simple in theory and can easily calculate the scattering matrices at the discontinuities with simple structure like iris coupled filters. Additionally the effect for finite thickness of the iris in the dual-mode cavity iflter is analyzed by te full-wave method, providing the exact filter implementation without trial and error.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.839-843
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• 2008

Receiving room's floor impact sound level is been influenced to various factor of slab thickness, room size, structure etc. This study examined the noise of upper part slab and room mode in receiving room to be importance factor that influence in receiving room level among this factors. According to this study, vibration mode in slab and room mode are concentrated on frequency that is high level relatively. This causes bad effect in floor impact sound level. Therefore, method to reduce floor impact sound level is to change vibration mode using slab upper part's resilient material or reduce room mode in receiving room.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.911-920
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• 1989

It this study, beam-type bend specimen is used to evaluate the interlaminar fracture toughness of laminated composite under mixed-mode deformations. The specimen is loaded under three-point bending and hence produced mixed-mode deformations in the vicinity of the crack tip according to the variation of the thickness ratio on delamination plane. Total energy release rate is obtained by elementary beam theory considering the effect of shear deformation. The partitioning of total value into mode-I and mode-II components is also performed. The mixed-mode interlaminar fracture toughness is evaluated by experiments on specimens with several thickness ratios of delamination plane. As the part of delamination plane is thicker, the effect of shear deformation on total energy release rate is increased. Beam-type bend specimen men may be applied to obtain informations on the mixed-mode interlaminar fracture behavior of laminated composites.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.34-39
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• 1995

Particle displacement distributions of the fundamental mode and overtone modes in an energy-frapped single resonator and an energy-trapped double acoustically coupled filter using the thickness shear vibration were calculated. And the effects of the width of a pair of partial electrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back on the displacement distributions of the symmetric vibration mode and anti-symmetric vibration mode of the resonators and the filters were investigated.

• Journal of the Optical Society of Korea
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• v.14 no.3
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• pp.277-281
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• 2010

We propose a design and optimization method for a dielectric-loaded surface plasmon polariton waveguide using a genetic algorithm. This structure consists of a polymer ridge on top of two layers of substrate and gold film. The thickness, width and refractive index of the ridge are designed to optimize the figures of merit including mode confinement and propagation length. The modal analysis combined with the effective index method shows that the designed waveguide exhibits a fundamental propagation mode with high mode confinement while ensuring that the propagation loss remains relatively low.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.53-54
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• 2008

We have studied electro-optic characteristics as a function of passivation thickness$(t_p)$ in the fringe-field swiching (FFS) mode using the LC with positive dielectric anisotropy. When $t_p$ is increased from $0.29{\mu}m$ to $3.0{\mu}m$, a maximum transmittance is slightly increased to $2{\mu}m$. However, operating voltage is continuously increased up to above 11v. We found that the tilt angle is decreased between the edge of pixel electrode and the center of each pixel electrode. In the FFS mode using the liquid crystal with positive dielectric anisotropy, transmittance is affected by the tilt angle. When tilt angle is increased, transmittance become decrease. Therefore, in the FFS device, a low tilt angle is favored for high transmittance. It is demonstrated that the suitable passivation thickness make a tilt angle decreased.

• The Journal of the Acoustical Society of Korea
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• v.36 no.3
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• pp.158-164
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• 2017

Typical hydrophones in line array sensors for early detection of covert underwater targets can measure only sound-pressure-magnitude with the limitation of being unable to identify the direction of an incoming wave. In this study, a thickness shear mode vibrator was proposed as the main component of an inertia type vector hydrophone to measure both magnitude and direction of acoustic signals from targets. The equation to analyze the output voltage of the vibrator to an external force was derived, and the validity of the equation was verified through finite element analysis of a PMN-PT single crystal vibrator. The analysis results from this study will be utilized in the future for the design of inertia type vector hydrophones made of thickness shear vibrators.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.3
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• pp.206-212
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• 2000

The guided wave mode conversion phenomena were investigated for the NDE of a plate-like structure with thickness variation. The ratios of reflection and transmission (R/T) were measured via the self-calibrating procedure which allows us to obtain experimental guided wave data in a more reliable way regardless of the coupling uncertainty between transducer & specimen. The results on R/T could be used to determine the thickness reduction of the structure. It was shown that not only the incident modes but also the converted ones need to be considered in the self-calibrating guided wave inspection to extract a reasonable correlation between experimental data & the thickness variation. Through this study, the potential of guided wave inspection as a quantitative NDE technique was explored based on the combined concept of self-calibration & multi-mode conversion in guided wave scattering problems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.685-689
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• 2005

In the fabrication and design of MLCCs (Multilayer Ceramic Capacitors) with Ni inner electrode for medium and high voltage, reliability and dielectric breakdown mode have been investigated. For thickness of green sheet, the relationship between the rated voltage versus the thickness of green sheet. Increasing the thickness of green sheet increases the dielectric breakdown voltage. However, a practical limit to this linear relationship occurs at 30 urn and above. As the thickness of green sheet increased, dielectric breakdown voltage and weibull coefficient is increased, but abruptly decrease at 30 urn and 36 urn. When 24 urn of green sheet thickness, weibull coefficient and dielectric breakdown voltage were 13.58 and 70 V/um respectively. The results enabling the MLCCs to demonstrate high levels of reliability at medium and high voltage.

• Journal of Welding and Joining
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• v.14 no.5
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• pp.69-77
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• 1996

This study aims to analyze the S. I. F. K value upon Mode I cracks in a finite-width plate of varying thickness, which is expressed in terms of width ratio ($\omega$), thickness ratio ($\beta$) and non-dimensional crack length (λ) by using the 2-dimensional finite element method. Then, by comparing the effectiveness of the results obtained by the two finite element methods, it is seen that the 2-dimensional finite element method can be used in order to analyse the S. I. F. K values upon a various thickness model. A model is developed in order to analyze the effects of initial residual stress upon the fatigue crack growth behavior in various thickness welded specimens. In this model, crack growth rate da/dN appears to be come small as the thickness ratio with the same ΔK is increased. Also, in the initial step, as ΔK is increased with crack growth rate is decreased and then increased because the repeated compressive residual stress retards crack growth rate.