• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1147-1151
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• 2004

A novel impedance model is proposed fur the rectangular power plane along with the analytic impedance expression derived from it. The power plane is modeled as a section of a rectangular waveguide with appropriate boundary conditions around its periphery. As a result, the derived impedance expression based on the proposed model has the one-dimensional series form, which is simpler and computationally more efficient than the existing formula based on cavity model of the power plane.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.1021-1028
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• 2004

Kim et al. suggested an experimental method to determine the Q parameter in situ from the out-of-plane displacement and the in-plane strains on the surface of side necking near the crack tip. In this paper, the procedure to evaluate the stress triaxiality near a crack tip such as the Q parameter is to be polished in the details for simplicity and accuracy. That is, Q and hydrostatic stress are determined only from the out-of-plane displacement, but not using in-plane strain, which is hard to measure. And also, the plastic modulus is determined by an alternative way. Through three-dimensional finite element analyses for a standard CT specimen with 20% side-grooves, the validities of the new procedures are examined in comparison to the old ones. The effect of location where the displacements are measured to determine the stress triaxiality is explored.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.319-324
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• 2001

Free non-linear vibration of a rotating thin ring with a constant speed is analyzed when the ring has both the in-plane and out-of-plane motions. The geometric non-linearity of displacements is considered by adopting the Lagrange strain theory for the circumferential strain. By using Hamilton's principle, the coupled non-linear partial differential equations are derived, which describe the out-of-plane and in-plane bending, extensional and torsional motions. The natural frequencies are calculated from the linearized equations at various rotational speeds. Finally, the computation results from three non-linear models are compared with those from a linear model. Based on the comparison, this study recommends which model is appropriate to describe the non- linear behavior more precisely.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.241-251
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• 2005

In this paper, we introduce a new algebraic method to characterize rational PH plane curves. And using this method, we study the algebraic characterization of generic strongly regular rational plane PH curves expressed in the complex formalism which is introduced by R.T. Farouki. We prove that generic strongly semi-regular rational PH plane curves are completely characterized by solving a simple functional equation H(f, g) = $h^2$ where h is a complex polynomial and H is a bi-linear operator defined by H(f, g) = f'g - fg' for complex polynomials f,g.

• Proceedings of the Korea Society of Mathematical Education Conference
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• 2007.06a
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• pp.37-50
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• 2007

What is a foundational element of plane geometry? Isn't it possible to constitute the contents of plane geometry from that element? In this paper, we suggest a view point that triangle is a foundational element of plane geometry. And take some examples of reconstruction of usually given contents and mathematical activity centered on the triangle in plane geometry.

• Coupled systems mechanics
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• v.10 no.2
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• pp.143-159
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• 2021

The theory of generalized thermo-magneto-electroelasticity is employed to obtain the plane wave solutions in an unbounded, homogeneous and transversely isotropic medium. Reflection phenomena of plane waves is considered at a stress free and thermally insulated surface. For incidence of a plane wave, the expressions of reflection coefficients and energy ratios for reflected waves are derived. To explore the characteristics of reflection coefficients and energy ratios, a quantitative example is set up. The half-space of the thermo-magneto-electroelastic medium is assumed to be made out of lithium niobate. The dependence of reflection coefficients and energy ratios on the angle of incidence is illustrated graphically for different values of electric, magnetic and thermal parameters.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.731-740
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• 1998

In the previous studies about prescription of preadjusted appliance, occlusal plane was used as a reference plane for crwon angulation (tip) measurement. But this reference plane is not parallel to the line connecting the facial axis points at which the centers of brackets are positioned (Andrews' plane), due to the curve of Spee. Therefore, we developed a new reference plane unaffected by the curve of Sun and more parallel to the Andrews' plane. It is an imaginary line connecting mesial and distal marginal ridges of each posterior tooth, and we named it 'marginal ridge plane'. In this study, crown angulations of posterior teeth of 29 normal occlusion samples were measured and measurements from both reference planes were compared. Crown angulation measurements measured from occlusal plane were different from crown angulation measurements from marginal ridge plane in the upper and lower 2nd molars (p<0.01), md 1st premolars (p<0.05). These results were analyzed as the crown angulation measurements from occlusal plane were affected by the curve of Spee. Crown angulations should be varied according to the amount of curve of Spee to maintain the continuity of marginal ridges. To solve this problem, determining bracket angulation as the bracket slot is parallel to the marginal ridge plane of each posterior teeth is recommended.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.8
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• pp.1-6
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• 2010

We report on the electrical properties of Ti/Al/Ni/Au (20 nm/ 150 nm/ 30 nm/ 100 nm) Ohmic contacts and the anisotropic conductivity of n-type ${\alpha}$-plane ([11-20]) GaN grown on $\gamma$-plane ([1-102]) sapphire substrates. The Ti/Al/Ni/Au Ohmic contacts and their sheet resistances are characterized by using the transfer length method (TLM) as a function of azimuthal angles. It is found that the specific contact resistance does not depend on the axis orientation and there are significant electrical anisotropy in ${\alpha}$-plane GaN films on $\gamma$-plane sapphire substrates, and the sheet resistance varies with azimuthal angles. The sheet resistance values in the direction parallel to m-axis [1-100] are 25% ~ 75% lower than those parallel to c-axis [0001] directions. Thus, Basal stacking faults (BSFs) are offered as a feasible source of the anisotropic mobility in defected m-axis direction because the band-edge discontinuities owing to the differential band gap structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.337-338
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• 2008

We have studied electro-optic characteristics of a high performance liquid crystal display using Fringe In-plane field Switching (FIS) mode. The strong electric fields cause more liquid crystals to reorient almost in plane above and between the pixel electrodes. As a result, the operation voltage is lower and transmittance is higher than those of Fringe Field Switching (FFS) and In-Plane Switching (IPS) modes. Apparently, the transmittance depends on voltage applied at the configurations of FIS mode which are proposed. Therefore, we have studied certain length of between electrodes for maximum transmittance and light intensity.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1878-1880
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• 2002

In this paper, electromagnetic waves radiated from discharge at three-type electrodes (needle-plane, plane-plane and sphere-plane electrode) using DC power source in air measured and the peculiar patterns of their spectra are reported. The radiated electrodmagnetic waves were measured in bandwidth of VHF($30{\sim}230$[MHz]) using a biconcal antenna and a spectrum analyzer. Frequency spectrum distribution of radiated electromagnetic wave was revealed under 50[MHz] at positive DC, and high electric field was shown at 45[MHz] frequency band. But, it was revealed under 70[MHz] frequency band at negative DC under plane-plane electrodes and sphere-plane electrodes, and high electric field was shown at 55 [MHz] frequency band.