• Applied Microscopy
• /
• v.47 no.2
• /
• pp.77-83
• /
• 2017

Drastic development of ubiquitous devices requires more advanced batteries with high specific capacitance and high rate capability. Large-area microstructure characterization across the stacks of cathode, electrolyte and anode might reveal the origin of the instability or degradation of batteries upon cycling charge. In this study, sample preparation methods to observe the cross-section view of the electrodes for battery in SEM and several imaging tips are reviewed. For an accurate evaluation of the microstructure, ion milling which flats the surface uniformly is recommended. Pros and cons of cross-section polishing (CP) with Ar ion and focused ion beam (FIB) with Ga ion were compared. Additionally, a modified but new cross-section milling technique utilizing precision ion polishing system (PIPS) which can be an alternative method of CP is developed. This simple approach will make the researchers have more chances to prepare decent large-area cross-section electrode for batteries.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.8 no.1
• /
• pp.17-22
• /
• 1983

Scattering of obliquely incident plane electromagnetic waves by an isotropic plasma coumn which is moving uniformly in the perpendicular direction to its axis is treated analytically on the basis of Lorentz transform and boundary conditions. The scattered field, the total scattering cross-section, the rader cross-section, and the angular distribution of the scattered power for the incident plane waves polarized arbitrarily are derived to find the function of the moving velocity of the plasma column and of the angle of the incident plane waves and to find the scattered field of the H-waves more distinguishable than the E-waves.

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.372-375
• /
• 1995

The magnetization pattern of the central cross section deduced from the ac susceptibility measurement is described with an analytical function. The function is based on a charge-free configuration. The thickness of the $^{\circ}$ wall lying in a (100) plane and the wall energy are calculated analytically. Total energy of the domain structure has been minimized with Ritz's method. As the result of the minimization, the energy density of the $^{\circ}$ wall lying in a (100) plane is $0.58\;erg/cm^{2}$ and the one for a (110) plane is $1.18\;erg/cm^{2}$. Thicknesses of these walls are calculated numerically. Also, the calculation indicates there is a small central domain at the cross section without applied current. With the ac susceptibility measurement the existence of the domain without current can be identified.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.9 s.180
• /
• pp.2191-2201
• /
• 2000

End effects due to sectional deformations of thin-walled beams with closed cross section are analysed by a one-dimensional theory. In particular, end effects associated with warping (out of plane m otion) and distortion (in plane motion) are investigated. The exact solutions as a vector form are newly derived to reveal slowly-decaying nature of the end effects in a thin-walled beam loaded by a couple. Several examples of thin-walled beams under various loading conditions indicate that the local end effect zone due to warping and distortion is approximately ten times the typical beam width.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.6
• /
• pp.64-73
• /
• 1996

The three-dimensional strength behavior of compacted decomposed granite soil was studied using cubical triaxial tests with independent control of the three principal stresses. All specimens were loaded under conditions of principal stress direction fixed and aligned with the directions of compacted plane. For comparable test conditions, the major principal strain and volume strain to failure were smallest when the major principal stress acted perpendicular to the compacted plane. The opposite extremes were obtained when the major principal stress acted parallel to the compacted plane. In cubical triaxial tests with same b values and with ${\theta}$ values in one of three sectors of the octahedral plane, independent of the range of ${\theta}$, higher friction angles are obtained in tests with b greater than in triaxial compression tests in which b 0.0, Comparison between the results of the drained cubical triaxial tests on lksan compacted decomposed granite soil and the cross section of the Mohr-Coulomb failure surface as well as the cross section of the Mohr-Coulomb failure surface were made. Lade's isotropic failure criterion based on vertical specimens overestimates the strengths for tests performed with values of 0 between 90˚ and 1 50˚ the Mohr-Coulomb criterion generally underestimates the strengths of tests performed with values of ${\theta}$ between $0^{\circ}$ and $180^{\circ}$ except around the $120^{\circ}$.

• Smart Structures and Systems
• /
• v.13 no.4
• /
• pp.659-683
• /
• 2014

The static analysis of structures with arbitrary cross-section geometry and material lamination via a refined one-dimensional (1D) approach is presented in this paper. Higher-order 1D models with a variable order of expansion for the displacement field are developed on the basis of Carrera Unified Formulation (CUF). Classical Euler-Bernoulli and Timoshenko beam theories are obtained as particular cases of the first-order model. Numerical results of displacement, strain and stress are provided by using the finite element method (FEM) along the longitudinal direction for different configurations in excellent agreement with three-dimensional (3D) finite element solutions. In particular, a layered thin-walled cylinder is considered as first assessment with a laminated conventional cross-section. An atherosclerotic plaque is introduced as a typical structure with arbitrary cross-section geometry and studied for both the homogeneous and nonhomogeneous material cases through the 1D variable kinematic models. The analyses highlight limitations of classical beam theories and the importance of higher-order terms in accurately detecting in-plane cross-section deformation without introducing additional numerical problems. Comparisons with 3D finite element solutions prove that 1D CUF provides remarkable three-dimensional accuracy in the analysis of even short and nonhomogeneous structures with arbitrary geometry through a significant reduction in computational cost.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.627-634
• /
• 2002

To facilitate a drilling plan for grouting in fractured rock, an algorithm of practical use associated with a new term “fracture density distribution”or“fracture tomogram”is developed. It is well known that Televiewer data(amplitude and traveltime image) provide detailed information about not only dip and dip direction of each fracture but also its aperture size estimated by an appropriate evaluation algorithm. A selected plane section of medium around a borehole or the cross section between two boreholes is discretized into a two dimensional grid of cells(rectangular elements). As each elongated(straight) fracture passes through the cells, the corresponding aperture size value is successively summed up in each cell, depending on the fracture length segment. In this, the fracture lines can be determined by intersecting of each fracture plane with the selected plane section. If the fracture line does not pass through a particular grid element, the segment length is set to zero. The final value(aperture size value of each cell) derived from all the detected fractures constitutes the fracture density distribution of the selected plane section, Field examples are illustrated, which will prove the benefit of the suggested algorithm for several kinds of grouting works.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.12
• /
• pp.1399-1405
• /
• 2012

Transmission cross section characteristics as a measure of transmission efficiency has been analyzed numerically for the H-shaped and C-shaped small apertures in the infinite conducting plane when illuminated by a plane wave. It has been found that C-shaped aperture has the larger transmission cross section than that of H-shaped aperture under the condition of the same perforated aperture area. Main attention has been focused on studying the mutual coupling effect between two C-shaped apertures on the transmission cross section characteristic. Parallel configuration which is composed of two C-shaped apertures arranged along the x-axis and collinear configuration which is composed of two C-shaped arrayed along the y-axis have been investigated from the viewpoint of enhanced transmission cross section characteristics.

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.78-81
• /
• 1987

The scattering characteristics are analysed for the dielectric cylinder with arbitrary cross section partially covered by thin conductors. The integro differential equations consistant with boundary conditions of conductor and dielectric boundaries are derived by the equivalence principle. They are transformed into matrix equations by moment method. The circular dielectric cylinder covered by conductors at the upper and bottom side of the cylinder is chosen for the numerical example. Current distributions on conductors and scattering cross section by the cylinder are computed for incident wave perpendicular to the conductor plane.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.10
• /
• pp.4706-4712
• /
• 2013

One of the efficient procedures for the solution of partial differential equations is the method of differential quadrature. This method has been applied to a large number of cases to circumvent the difficulties of programming complex algorithms for the computer, as well as excessive use of storage due to conditions of complex geometry and loading. Under in-plane uniform distributed load, the buckling of asymmetric curved beam with varying cross section is analyzed by using differential quadrature method (DQM). Critical load due to diverse cross section variation and opening angle is calculated. Analysis result of DQM is compared with the result of exact analytic solution. As DQM is used with small grid points, exact analysis result is shown. New result according to diverse cross section variation is also suggested.