• Geomechanics and Engineering
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• v.12 no.3
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• pp.347-360
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• 2017

The problem of cylindrical cavity expansion incorporating deformation dependent of intermediate principal stress in rock or soil mass is investigated in the paper. Assumptions that the initial axial total strain is a non-zero constant and the axial plastic strain is not zero are defined to obtain the numerical solution of strain which incorporates deformation-dependent intermediate principal stress. The numerical solution of plastic strains are achieved by the 3-D plastic potential functions based on the M-C and generalized H-B failure criteria, respectively. The intermediate principal stress is derived with the Hook's law and plastic strains. Solution of limited expansion pressure, stress and strain during cylindrical cavity expanding are given and the corresponding calculation approaches are also presented, which the axial stress and strain are incorporated. Validation of the proposed approach is conducted by the published results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.11-21
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• 2002

A series of model tests is performed to evaluate the relationship between soil and a buried pipe in soil undergoing lateral movement. As the result of the model tests, a wedge zone and plastic flow zones could be observed in front of the pipe. And also an arc failure of cylindrical cavity could be observed at both upper and lower zones. Failure shapes in both cohesionless and cohesive soils are nearly same, which was investigated failure angle of $45^{\circ}+{\phi}/2$. In the cohesionless soil, the higher relative density produces the larger arc of cylindrical cavity. On the basis of failure mode observed from model tests, the lateral earth pressure acting on a buried pipe in soil undergoing lateral movement could be applying the cylindrical cavity extension mode. The deformation behavior of soils was typically appeared in three divisions, which are elastic zones, plastic zones and pressure behavior zones.

• Journal of electromagnetic engineering and science
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• v.2 no.2
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• pp.100-104
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• 2002

A proper equivalent circuit model for coupling iris has been derived in order to compensate the length of cavity in a $TE_{011}$TEX> mode cylindrical cavity filter. A method to resolve the difference in bandwidth and feature or ripple systematically has been proposed. This method can be applied to other types of waveguide cavity filter.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.341-342
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• 2008

A conductivity of soot at microwave frequency is presented using a novel technique for complex permittivity of materials. The method overcomes limitations of conventional methods which are cavity perturbation and transmission/reflection method. Resonant frequencies and Q factors are measured and simulated for the cylindrical cavity, and they are compared to each other. Similar material property of both real material and simulation material produce similar values of resonant frequency and Q factor. The complex permittivity of material can be determined by simulating the cavity to change material property until the simulation results are nearly the same as the measurement results. Cylindrical cavity has been realized for measurement at 880 MHz, and conductivity of soot is measured. A sample was made by depositing the soot on the glass. The proposed method shows that the conductivity of soot is 11 S/m.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.267-270
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• 2000

This paper describes measurement of relative permittivity of illite found in young-dong area. A measurement of relative permittivity of illite used to cylindrical cavity resonators with moveable cap. A concentric dielectric-rod inserted cylindrical cavity resonator and an exact field representation of travelling wave mode are introduced for measurement of relative permittivity. The exact electromagnetic fields in cylindrical cavity with concentric dielectric rod is analysed. A relative permittivity of dielectric in cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. We know that the field representation of travelling mode is exact. As a result, relative permittivity of dielectric materials were 7.820 at sample-1 and 7.894 at sample-2.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1069-1072
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• 2001

We described a method resonant mode identification in dielectric-rod loaded cylindrical cavity resonators. Resonant frequency of dielectric loaded cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. As the result of comparing calculation value and experimental value of resonant frequencies, we know that the field representation of non-decaying mode is exact. The contour graph method is not a method using approximated representation of electromagnetic field variation at the outer area of dielectric in the resonators but a method using exact representation.

• 전기의세계
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• v.28 no.2
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• pp.68-75
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• 1979

The penetration of an electro-magnetic wave through an aperture in a cylindrical structure with a center dielectric-rod is investgated. By using a standard mode matching procedure, the electrical and magnetic fields in a cavity are determined as a function of position inside the cavity and frequency of the incident field. For the given parameters, computed data are obtained and the results exhibited in form of amplitude curves of the nor malized field and energy densities of functions of position and frequency. Depending on the increase of the relative dielectric constant of center dielectric-rod, the resonance frequecies of the cavity vary as the cavity size decrease. The stored electro-magnetic energy varies very rapidly as a function of position inside the cavity and of the source frequency. Its peak value can be two orders of magnitude greater than the incident energy density. The frequencies where the peaks occur can be identified approximately as the resonance frequencies of the cavity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1731-1740
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• 1995

Experimental investigations have been made to study the double-diffusive nature of convection of an initially stratified salt-water solution due to heating from below in a rotating cylindrical cavity. The objective is to examine the flow phenomena and the heat transfer characteristics according to the changes in temperature gradient, concentration gradient and rotating velocity of cavity. Thermal and solutal boundary conditions at side wall are adiabatic and impermeable, respectively. The top and bottom plate are maintained each at constant temperature and concentration. The cavity is put into a state of solid body rotation. Like the stationary case, the types of initially-formed flow pattern are classified into three regimes depending on the effective Rayleigh number and Taylor number; stagnant flow regime, single mixed-layer flow regime and successively formed multi-mixed layer flow regime. At the same effective Rayleigh number, the number of initially-formed mixed layer and its growth rate decrease as the effect of rotation increases. The temperature and concentration profiles are both uniform in each layer due to convective mixing in the layered-flow regime, but look both liner in stagnant flow regime and single mixed-layer flow regime. At the interface between adjacent layers, the temperature changes smoothly but the concentration changes rapidly.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1115-1121
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• 2008

In this paper, dielectric slab loaded cylindrical cavity resonator measurement technique is presented to determine the dielectric constant of a dielectric material. The dielectric constant is measured by the resonant frequency deviation of empty and dielectric slab loaded cavity. Characteristic equations are derived by th exact field analysis. The measurement configurations are formed using HP8719A vector network analyzer and an experimental cylindrical metallic cavity with circular cross-section. The validity of the theory is confirmed by experiments and CST MWS 4.0(3D simulator). The results were in the whole satisfactory. The measured dielectric constant of teflon and bakelite are 2.03 and 4.44, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.791-794
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• 2001

We described a method resonant mode identification in dielectric-disc loaded cylindrical cavity resonators. The characteristic equation is solved by using the ContourPlot graph of Mathematica. Contour graph method uses graphical method. It is comparable with numerical method. The numerical method is very difficult a mode identification. The analysis based on the approximated electromagnetic representation. This kinds of studies only concentrated on the calculation of resonant frequencies, and a mode identification of resonant frequencies have not been covered. But, the contour graph method to analyze the characteristic equations is simple and all parts of resonant frequency graph can be easily drawn, it is possible to calculate precise resonant frequencies and to identify the mode of resonant frequencies.