• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.715-720
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• 1991

The electromagnetic fields radiated from an aperture on a conducting plance covered with a moving uniaxial plasma layer are analyzed. From wave equations in moving plasma and free space region, their solutions are obtained and radiation fields are determined by applying proper boundary conditions in each region. For a particular case of isotropic plasma layer, our results correspond to well-known results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.11a
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• pp.11-14
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• 2001

3-D compressible flow analysis was conducted by using mixing plane method for turbine system which is consisted of partial admission nozzle and rotor. Computational results are shown oblique shock wave in blade leading and trailing edge and also shown flow separation along suction surface of blade due to abrupt blade curvature. But computational results are well agree with 1-D calculation results and experimental data.

• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.1-5
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• 2015

A high-frequency analysis technique, called the hidden rays of diffraction (HRD), is reviewed in this paper. The physical optics and the rigorous diffraction coefficients of a perfectly conducting wedge illuminated by a plane wave are compared. The physical existence of hidden rays on the shadow boundary is explained in view of the geometric theory of diffraction (GTD). In particular, a systematic tracing of hidden rays and its visualization are precisely described by introducing the concept of the supplementary boundary. The physical meaning of the null-field condition in the complementary region is also explained.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.105-109
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• 1987

A solution which combines ray and aperture integration(AI) techniques is presented for the problem of electromagnetic plane wave scattering by an open-ended, perfectly-conducting, semi-infinite parallel plate waveguide with a thin, uniform layer of lossy or absorbing material on its inner walls, and with a simple planar termination inside. Numerical results are given for the fields outside the waveguide.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.385-390
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• 1996

It has been well known that the Grad thirteen-moment equations have solutions only when the Mach number is less than a limiting value for the stationary plane shock-waves. The limit of Mach number has been re-examined by including successive terms in the series expansion of distribution function. The method employed is the linear analysis of moment equations near up-streaming and down-streaming flows. For the thirteen moment case, it has been confirmed that equations have solutions only when the Mach number is less than 1.6503, which is consistent with the literature value. For the case of twenty moments, the limit of Mach number is decreased to 1.3416.

• Geomechanics and Engineering
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• v.31 no.2
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• pp.159-166
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• 2022

The model of two-dimensional plane waves is analyzed in a micropolar-thermoelastic solid with microtemperatures in the context of the three-phase-lag model, dual-phase-lag model, and the Green-Naghdi theory of type III. Harmonic wave analysis is used to hold the solution to the problem. Numerical results of the physical fields are visualized to show the effects of the gravity field, magnetic field, and viscosity. The expression for the field variables is obtained generally and represented graphically for a particular medium.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.2
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• pp.65-75
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• 1984

A comparative study between several methods for the marine drilling riser analysis is carried out. One static analysis method and four dynamic methods are studied. The dynamic analysis methods used are two time domain methods using regular and random waves, and two frequency domain methods using the conventional and an improved linearization techniques. Two different sizes of risers are investigated. The analysis model of the structure is based on the beam-column element with lateral wave/current loads in a vertical plane. The forces on the riser are calculated using a modified farm of the Morison's equation. The finite element method is used to solve the equation for several wave/current conditions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.192-199
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• 2002

The use of frequency-dependent dynamic stiffness matrix (or spectral element matrix) in structural dynamics may provide very accurate solutions, while it reduces the number of degrees-of-freedom to improve the computational efficiency and cost problems. Thus, this paper develops a spectral element model for the thin plates moving with constant speed under uniform in-plane tension. The concept of Kantorovich method is used in the frequency-domain to formulate the dynamic stiffness matrix. The present spectral element model is evaluated by comparing its solutions with the exact analytical solutions. The effects of moving speed and in-plane tension on the flexural wave dispersion characteristics and natural frequencies of the plate are numerically investigated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.1-5
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• 2010

This paper deals with a method to measure the thickness of scale-layer, iron oxide formed on the surface of the rolling steel, using a dielectric lens antenna. The dielectric lens antenna has an independent characteristic with the frequency in the X-band and changes the spherical wave radiated from a horn antenna into a plane wave at the focusing point. Using this concept, we regard a scale-layer on the rolling steel as a dielectric-PEC(Perfect Electric Conductor) layer and apply a theoretical analysis of the normal-incident plane wave. To reduce the phase error arising from the use of the dielectric lens antenna, this paper utilizes a regression process algorithm. In comparison with the conventional iteration algorithm, the present algorithm led to a unique solution for the thickness of the scale-layer.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3E
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• pp.31-37
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• 2001

Finite element model of a cMUT is constructed using the commercial code ANSYS to analyze the cross talk mechanism. Calculation results of the complex load impedance seen by single capacitor cells are presented, and then followed by a calculation of the plane wave real load impedance seen by a parallel combination of many cells that are used to make a transducer. Cross talk between 1-D array elements is found to be due to two main sources: coupling through a Stoneley wave propagating at the transducer-water interface and coupling through Lamb waves propagating in the substrate. To reduce the cross talk level, the effect of various structural variations of the substrate are investigated, which include a change of its thickness and etched trenches or polymer walls between array elements.