• Journal of the Korean Ceramic Society
• /
• v.44 no.6 s.301
• /
• pp.319-324
• /
• 2007

The structural properties of $SiO_2$ liquid at finite temperatures have been investigated by molecular dynamics (MD) simulations utilizing the Tersoff interatomic potential. During cooling process, the $SiO_2$ liquid structure quenched with a cooling rate of $1.0{\times}10^{11}K/sec$ shows the traditional properties observed in the experiments. The coordination defects of system decrease with decreasing temperature up to 17%. The $SiO_2$ glass quenched up to 1600 K contains defects consisting of the fivefold coordination of Si, and the threefold coordination of O atoms. The calculated diffusion coefficients which are calculated by monitoring. the mean-square displacement of atoms drop to almost zero below 3000 K ($<10^{-6}\;cm^2/sec$) but has a fluctuations at low temperature. The structure properties of $SiO_2$ liquid shows a significant dependence on the temperature during cooling process. Bond-angle distribution at around $120^{\circ}$ originate from the O and Si atoms consisting of the over-coordinated O atoms.

• Honam Mathematical Journal
• /
• v.26 no.1
• /
• pp.3-15
• /
• 2004

In the fuzzy theory, a matrix A is idempotent if $A^2=A$. The idempotent fuzzy matrices are important in various applications and have many interesting properties. Using the upper diagonal completion process, we have the zero patterns of idempotent fuzzy matrix, that is, the idempotent Boolean matrices. In addition, we give the construction of all idempotent fuzzy matrices for each dimension n.

• Journal of the military operations research society of Korea
• /
• v.8 no.2
• /
• pp.57-68
• /
• 1982

Bimatrix games are the two-person non-zero-sum non-cooperative games. These games were studied by Mills, Lemke, Howson, Millham, Winkels, and others. This paper is a systematic and synthetic survey relevant to bimatrix games. Among the many aspects of researches on bimatrix games, emphasis in this paper is placed on the relation of the equilibrium set to Nash subsets. Topics discussed are as follows: Properties of equilibrium point; The structure of equilibrium set; Relation of Nash subsets to equilibrium set; Algorithm for finding the equilibrium points; Concepts of solutions on bimatrix games.

• Communications of the Korean Mathematical Society
• /
• v.26 no.4
• /
• pp.591-601
• /
• 2011

In this paper, we deal with the discrete p-Laplacian operators with a potential term having the smallest nonnegative eigenvalue. Such operators are classified as its smallest eigenvalue is positive or zero. We discuss differences between them such as an existence of solutions of p-Laplacian equations on networks and properties of the energy functional. Also, we give some examples of Poisson equations which suggest a difference between linear types and nonlinear types. Finally, we study characteristics of the set of a potential those involving operator has the smallest positive eigenvalue.

• Honam Mathematical Journal
• /
• v.39 no.3
• /
• pp.317-330
• /
• 2017

In this paper we introduce some new kinds of injectivities, namely, LC (resp. Ind, PInd) injectivity and investigate the relation among various kinds of injectivities. Some classifications of monoids by properties of these kinds of injective acts are presented. Among other results, it is shown that over a principal right ideal monoid, right completely LC-injectivity implies right completely injectivity. Also over a monoid with a zero Ind-injective (resp. PInd-injective) acts are injective.

• Kyungpook Mathematical Journal
• /
• v.57 no.4
• /
• pp.559-580
• /
• 2017

Let G be an arbitrary group with identity e and let R be a G-graded ring. In this paper, we define the concept of graded 2-absorbing and graded weakly 2-absorbing primary ideals of commutative G-graded rings with non-zero identity. A number of results and basic properties of graded 2-absorbing primary and graded weakly 2-absorbing primary ideals are given.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10a
• /
• pp.313-318
• /
• 1998

Generally, the concrete constructed during cold weather has the frozen damage which cause the fatal damage so that heat curing and sheet curing was performed to prevent the early freezing of concrete. However, partial refrigeration caused by thermal gradient has many troubles so that the construction hasn`t been done as possible. This paper presents the development of strenth properties and optimal mix design against frozen damage under the cold weather, 1$0^{\circ}C$ below the zero.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.36 no.5 s.108
• /
• pp.78-84
• /
• 2004

Lignin precipitated from black liquor of soda pulping of bagasse was used to prepare cation-exchange resin. The effect of sulfuric acid treatment, concentration of phenol and formaldehyde on the properties of the prepared cation-exchange resin was investigated. It was found that sulfonated resinified phenolated lignin gave a resin with an ion-exchange capacity higher than that of resin, which resulted from sulfonation of resinified lignin at zero phenol concentration. Infrared spectroscopy of the prepared ion-exchange resin shows anew bands at 1060, 1160, 1280 and $1330\;cm^{-1}$ which indicated to the presence of $SO_{3}$.

• The Pure and Applied Mathematics
• /
• v.17 no.2
• /
• pp.131-136
• /
• 2010

Throught this paper, we will investigate some properties of left regular and strongly reduced near-rings. Mason introduced the notion of left regularity and he characterized left regular zero-symmetric unital near-rings. Also, this concept have been studied by several authors. The purpose of this paper is to find some characterizations of the strong reducibility in near-rings, and the strong regularity in near-rings which are closely related with strongly reduced near-rings.

• Bulletin of the Korean Mathematical Society
• /
• v.47 no.2
• /
• pp.231-249
• /
• 2010

Asymptotic behavior of three-dimensional mixed, periodic and rotating magnetohydrodynamic system is investigated as the Rossby number goes to zero. The system presents the difficulty to be singular and mixed, that is hyperbolic in the vertical direction and parabolic in the horizontal one. The divergence free condition and the spectral properties of the penalization operator are crucial in the proofs. The main tools are the energy method, the Schochet's method and products laws in anisotropic Sobolev spaces.