• Journal of Information Display
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• 제13권3호
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• pp.97-100
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• 2012

We have conducted two kinds of the so-called charge-compensated aliovalent element substitutions to control the photoluminescence properties of $NaAlSiO_4:Eu^{2+}$ with a special focus on the enhancement of the excitation intensity at 400 nm. The aliovalent element substitutions include cation-cation and cation-anion co-substitutions according to the general formulas $Na_{1-x}M_xAl_{1+x}Si_{1-x}O_4:Eu^{2+}$ and $Na_{1-x}M_xAlSiO_{4-x}N_x:Eu^{2+}$ (M = $Mg^{2+}$, $Ca^{2+}$, and $Sr^{2+}$), respectively. The increase in the relative excitation intensity at 400 nm has been achieved in both types of the co-substitutions. Thus, the present research has demonstrated the effectiveness of the charge-compensated element substitution.

• 대한수학회논문집
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• 제35권2호
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• pp.455-468
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• 2020

An element in a ring R with identity is called invo-clean if it is the sum of an idempotent and an involution and R is called invoclean if every element of R is invo-clean. Let C(R) be the center of a ring R and g(x) be a fixed polynomial in C(R)[x]. We introduce the new notion of g(x)-invo clean. R is called g(x)-invo if every element in R is a sum of an involution and a root of g(x). In this paper, we investigate many properties and examples of g(x)-invo clean rings. Moreover, we characterize invo-clean as g(x)-invo clean rings where g(x) = (x-a)(x-b), a, b ∈ C(R) and b - a ∈ Inv(R). Finally, some classes of g(x)-invo clean rings are discussed.

• Korean Journal of Mathematics
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• 제21권3호
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• pp.319-323
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• 2013

Let D be a principal ideal domain, X be an indeterminate over D, D[X] be the polynomial ring over D, and $R_n=D[X]/(X^n)$ for an integer $n{\geq}1$. Clearly, $R_n$ is a commutative Noetherian ring with identity, and hence each nonzero nonunit of $R_n$ can be written as a finite product of irreducible elements. In this paper, we show that every irreducible element of $R_n$ is a primary element, and thus every nonunit element of $R_n$ can be written as a finite product of primary elements.

• Kyungpook Mathematical Journal
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• 제51권3호
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• pp.339-344
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• 2011

Let D be an integral domain with quotient field K, X be an indeterminate over D, and D[X] be the polynomial ring over D. A prime ideal Q of D[X] is called an upper to zero in D[X] if Q = fK[X] ${\cap}$ D[X] for some f ${\in}$ D[X]. In this paper, we study integral domains D such that every upper to zero in D[X] contains a prime element (resp., a primary element, a t-invertible primary ideal, an invertible primary ideal).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.84-87
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• 2003

The interfacial diffusion in Fe/Cr/MgO(001) multilayers has been studied using synchrotron x-ray techniques, such as x-ray reflectivity, extended x-ray absorption fine structures (EXAFS), and anomalous x-ray scattering (AXS). The results of x-ray reflectivity indicated that the interfacial roughness of Fe/Cr multilayers with Cr-$4{\AA}$-thick was larger than that with Cr-$4{\AA}$-thick. The results of EXAFS indicated that the Fe element dominantly diffuse into the stable Cr layers at the Fe/Cr interface. The AXS was certified the existence of the interdiffused Fe element in the Cr layers. Our study revealed that the rough interface of the Fe/Cr multilayers was caused by the interfacia diffusion of Fe element into the Cr layers.

• 한국자기학회지
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• 제3권4호
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• pp.314-319
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• 1993

Co-12at%Cr-2at%Ta/Cr-X 자성박막의 자기적성질과 미세구조에 미치는 첨가원소 X(X=Si, Mo, Cu, Gd)의 영향에 대해 조사하였다. Cr-X 하지층 및 CoCrTa 자성층의 두께는 각각 $1000~2000\AA$과 $200~800\AA$이었으며, 기판온도는 $100~200^{\circ}C$로 변화시켰다. Cr-X 하지층은 순수한 Cr 하지층에 비하여 보자력이 100 Oe~200 Oe 이상 증가하였다. Cu는 Gd, Mo, Si보다 높은 보자력 을 나타내는 Cr-X 하지층의 첨가원소 였으며 CoCrTa/Cr-Cu 자성박막은 하지층두께 $1500\AA$과 자성층두께 $600\AA$에서 높은 보자력을 나타내었다.

• 대한기계학회논문집
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• 제18권1호
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• pp.101-112
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• 1994

The measurement of residual stress distribution of $Si_3N_4/SUS304$ joint was performed on 23 specimens with the same joint condition using PSPC type X-ray stress measurement system and the two-dimensional elastoplastic analysis using finite element method was also attempted. As results, residual stress distribution near the interface on the ceramic side of the joint was revealed quantitatively. Residual stress on the ceramic side of the joint was turned out to be tensional near the interface, maximum along the edge, varying in accordance with the condition of the joint and variance to be most conspicuous for the residual stress normal to the interface characterized by the stress singularities. In the vicinity of the interface, the high stress concentration occurs and residual stress distributes three-dimensionally. Therefore, the measured stress distribution differed remarkably from the result of the two-dimensional finite-element analysis. Especially at the center of the specimen near the interface, the residual stress, $\sigma_{x}$ obtained from the finite element analysis was compressive, whereas measurement using X-ray yielded tensile $\sigma_{x}$. Here we discuss two dimensional superposition model the discrepancy between the results from the two dimensional finite element analysis and X-ray measurement.

• 대한수학회보
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• 제31권2호
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• pp.187-192
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• 1994

The author extended the small properties of topological semilattices to that of regular semigroups [3]. In this paper, it could be shown that a semigroup S is almost regular if and only if over bar RL = over bar R.cap.L for every right ideal R and every left ideal L of S. Moreover, it has shown that the Bohr compactification of an almost regular semigroup is regular. Throughout, a semigroup will mean a topological semigroup which is a Hausdorff space together with a continuous associative multiplication. For a semigroup S, we denote E(S) by the set of all idempotents of S. An element x of a semigroup S is called regular if and only if x .mem. xSx. A semigroup S is termed regular if every element of S is regular. If x .mem. S is regular, then there exists an element y .mem S such that x xyx and y = yxy (y is called an inverse of x) If y is an inverse of x, then xy and yx are both idempotents but are not always equal. A semigroup S is termed recurrent( or almost pointwise periodic) at x .mem. S if and only if for any open set U about x, there is an integer p > 1 such that x$^{p}$ .mem.U.S is said to be recurrent (or almost periodic) if and only if S is recurrent at every x .mem. S. It is known that if x .mem. S is recurrent and .GAMMA.(x)=over bar {x,x$^{2}$,..,} is compact, then .GAMMA.(x) is a subgroup of S and hence x is a regular element of S.

• 한국자기학회지
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• 제24권2호
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• pp.66-69
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• 2014

유한요소법으로 분할 표시한 연한 X-선 퍼짐관을 설계하였다. 연한 X-선관의 모양설계 및 구체적인 좌표를 설정하고 전자빔 궤적을 OPERA-3D SW 프로그램을 이용하여 시뮬레이션하였다. 음극과 양극인 텅스텐 필라멘트와 타겟에 인가한 전압, 온도, 열전자 일함수 등을 고정하였다. 필라멘트 십자형 모양을 구비한 퍼짐관의 구조에 따른 전자빔의 분포와 초점변화를 분석하여 반도체 공정상의 정전기장 제거용 연한 X-선 퍼짐관 설계를 최적화하였다.

• Steel and Composite Structures
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• 제37권6호
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• pp.663-678
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• 2020

This paper proposes a novel topology optimization method generating multiple materials for external linear plane crack structures based on the combination of IsoGeometric Analysis (IGA) and eXtended Finite Element Method (X-FEM). A so-called eXtended IsoGeometric Analysis (X-IGA) is derived for a mechanical description of a strong discontinuity state's continuous boundaries through the inherited special properties of X-FEM. In X-IGA, control points and patches play the same role with nodes and sub-domains in the finite element method. While being similar to X-FEM, enrichment functions are added to finite element approximation without any mesh generation. The geometry of structures based on basic functions of Non-Uniform Rational B-Splines (NURBS) provides accurate and reliable results. Moreover, the basis function to define the geometry becomes a systematic p-refinement to control the field approximation order without altering the geometry or its parameterization. The accuracy of analytical solutions of X-IGA for the crack problem, which is superior to a conventional X-FEM, guarantees the reliability of the optimal multi-material retrofitting against external cracks through using topology optimization. Topology optimization is applied to the minimal compliance design of two-dimensional plane linear cracked structures retrofitted by multiple distinct materials to prevent the propagation of the present crack pattern. The alternating active-phase algorithm with optimality criteria-based algorithms is employed to update design variables of element densities. Numerical results under different lengths, positions, and angles of given cracks verify the proposed method's efficiency and feasibility in using X-IGA compared to a conventional X-FEM.