• The Mathematical Education
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• v.46 no.3
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• pp.303-314
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• 2007

In this paper we try to study a method of constructing plane sections of regular tetrahedron and regular hexahedron. In order to construct plane sections of regular tetrahedron and regular hexahedron first of all, we extract some base problems that are used for construction. And we describe construction process using base problems in detail.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.6
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• pp.814-821
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• 2000

The Discrete Ordinates Interpolation Method (DOIM) is tested in three-dimensional enclosures. The radiative transfer equation (RTE) is solved for a linear source term and the DOIM is formulated for a gray medium. Several interpolation methods can be applied to the DOIM scheme. Among them, the interpolation method applicable to an unstructured grid system is discussed. In a regular hexahedron enclosure, radiative wall heat fluxes are calculated and compared with exact solutions. The enclosure has an absorbing, emitting and nonscattering medium and a constant temperature distribution. These results are obtained with varying optical depths (xD = 0.1, 1.0, 10.0). Also, the same calculations are performed in an irregular hexahedron enclosure. The DOIM is applied to an unstructured grid system as well as a structured grid system for the same regular hexahedron enclosure. They are compared with the exact solutions and the computational efficiencies are discussed. When compared with the analytic solutions, results of the DOIM are in good agreement for three-dimensional enclosures. Furthermore, the DOIM can be easily applied to the unstructured grid system, which proves the reliability and versatility of the DOIM.

• Journal for History of Mathematics
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• v.14 no.2
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• pp.115-124
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• 2001

In this paper, we developed a Web application program that could show the shape, the number of the vertices, the edges, the faces and development figures of polygons(regular tetrahedron, regular hexahedron, etc). The program was implemented using GSP(Geometer's SketchPad) and then converted to JAVA to display the results of GSP on the Web. The results of this paper are applicable to geometry of a junior high school course.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.3
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• pp.14-21
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• 1994

In this paper, a numerical method to be obtain the radar cross section(RCS) of three- dimensional bodies with arbitrary geometry and material compositions on the electromagnetic field with arbitrary incident angle is described. The RCS is obtained by solving the individual surface integral equation about multilayers scatterer using the three-dimensional bonudary element method(BEM). To show propriety and usefulness as to the three-dimensional BEM in this paper, the choice of a geometry is a multi-regular hexahedron and multi-right-angled hexahedron out of oblique incident electric field, and is considered to apply to every condition with loss sufficiently.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.202-206
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• 2001

The characteristics of heat transfer on the fire clay with microwave heating are numerically investigated using finite element method. The modelled regular hexahedron chamber($50cm{\times}50cm{\times}50cm$) filled with air consists of vertical heat source and sink walls, a fire clay model, and adiabatic plates at the top and bottom walls. With different geometrical aspect ratios of the fire clay model, the heat energy distribution is throughly investigated. The optimal shape of the fire clay for given chamber geometry and microwave power is analyzed.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.61-74
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• 1993

A new three-dimensional transition solid element was presented for the automated three-dimensional adaptive h-refinement or the local mesh refinement where the steep stress gradient exists. The proposed transition element was established by adding variable nodes(element nodes) to basic 8-node for an effective connection between the refined region and the coarse region with minimum degrees of freedom possible. To be consistent in accuracy with 8-node solid element with nonconforming modes, this transition element was also improved through the addition of the modified nonconforming modes. Numerical examples show that the performance of the element and the applicability to 3D adaptations are satisfactory.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.752-757
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• 2001

The characteristics of heat energy distribution on the fire-proof clay with microwave heating drying are numerically investigated using finite element method. The modelled regular hexahedron chamber$(50cm\times50cm\times50cm)$ filled with air consists of vertical heat source and sink walls, a fire-proof clay model, and adiabatic plates on the top and bottom walls. With different geometrical aspect ratios of the fire-proof clay model, the heat energy distribution is throughly investigated. The model gave a good prediction of the microwave heating characteristics of fire-proof clay. The optimal shape of the fire-proof clay for given chamber geometry and microwave power is analyzed.

• Journal of the Korean Data and Information Science Society
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• v.15 no.4
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• pp.717-729
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• 2004

The contour method which was originally designed for $2{\times}2{\times}2$ contingency table is studied for $2{\times}2{\times}K$ and $2{\times}3{\times}K$ tables. Whereas a contour plot for a $2{\times}2{\times}K$ table is represented on unit squared two dimensional plane, a contour plot of a $2{\times}3{\times}K$ table can be expressed with a regular hexahedron on three dimensional space. Based on contour plots for categorical data fitted to all possible three dimensional log-linear models, one might identify whether $2{\times}2{\times}k$ or $2{\times}3{\times}K$ tables are collapsible over the third variable.

• Journal of Powder Materials
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• v.18 no.6
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• pp.488-495
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• 2011

This study was performed to fabricate the porous titanium foam by space holder method using NaCl powder, and to evaluate the effect of NaCl volume fractions (33.3~66.6 vol.%) on the porosities, compressive strength, Young's modulus and permeability. For controlling pore size, CP titanium and NaCl particles were sieved to different size range of 70~150 ${\mu}m$ and 300~425 ${\mu}m$ respectively. NaCl of green Ti compact was removed in water followed by sintered at $1200^{\circ}C$ for 2 hours. Total porosities of titanium foam were in the range of 38-70%. Pore shape was a regular hexahedron similar that of NaCl shape. Porous Ti body showed that Young's modulus and compressive strength were in the range of 0.6-6 GPa and 8-127 MPa respectively. It showed that pore size and mechanical properties of Ti foams was controllable by NaCl size and volume fractions.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.307-312
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• 2011

Purpose: The purpose of this study is a porous cube mechanical analysis for the dental implant. Methods: The porous cube with a side length of 10mm was designed for dental implant. To choose proper design, porous hexagon with a side 10mm which was drilled as a regular hexagon with diameter 0.8mm, 1.0mm, 1.2mm and a side 0.4mm, 0.5mm, 0.6mm each using Computer AUTO CAD(Autodesk, 2008). Each cube was carried out in the mechanical analysis. Results: The result of mechanical analysis was observed that the H0.8 was minimum stress 0.045068MPa, maximum stress 9.4565MPa and minimum strain $0.00389{\times}10^{-4}Mpa$, maximum strain $0.816{\times}10^{-4}Mpa$, the H1.0 minimum stress 0.001147MPa, maximum stress 9.099MPa and minimum strain $0.000099{\times}10^{-4}Mpa$, the maximum strain $0.784{\times}10^{-4}Mpa$, the H1.2 minimum stress 0.099393MPa, maximum stress 13.137MPa and minimum strain $0.0112{\times}10^{-4}Mpa$, maximum strain $1.13{\times}10^{-4}Mpa$. Conclusion: The mechanical analysis of porous hexahedron was that H1.0 is the best result. It will be applicable to the porous implants.