• Macromolecular Research
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• v.17 no.11
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• pp.907-911
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• 2009

To improve the moisture stability of the $CaS:Eu^{2+}$ red phosphor, surface coatings with silica nanoparticles were performed using five different methods, i.e., $P_1$, $P_2$, $P_3$, $P_4$, and $P_5$. The phosphors were coated with silica nanoparticles using a dip coating method ($P_1$) and sol-gel method ($P_2$). The phosphors were coated using a solution containing silica nanoparticles and poly(1-vinyl-2-pyrrolidone), PVP, $(P_3$). The phosphors were also coated with silica nanoparticles by reacting with the 1-vinyl-2-pyrrolidone (VP) monomer ($P_4$) or by reacting with mixtures containing VP and tetraethylorthosilicate ($P_5$). A decrease in the photoluminescence (PL) intensity was observed regardless of the coating methods. However, the moisture stability of the phosphors was enhanced by the coating when aged in a temperature-controlled humidity chamber. Among these methods, the $P_4$ (or $P_5$) method exhibited the greatest increase in moisture stability of the phosphors. The coated phosphors showed a relatively constant intensity with aging time, whereas the uncoated phosphor showed a decrease.

• Bulletin of the Korean Mathematical Society
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• v.48 no.4
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• pp.673-688
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• 2011

Let $n{\geq}2$ be an even integer. We investigate that if an odd mapping f : X ${\rightarrow}$ Y satisfies the following equation $2_{n-2}C_{\frac{n}{2}-1}rf\(\sum\limits^n_{j=1}{\frac{x_j}{r}}\)\;+\;{\sum\limits_{i_k{\in}\{0,1\} \atop {{\sum}^n_{k=1}\;i_k={\frac{n}{2}}}}\;rf\(\sum\limits^n_{i=1}(-1)^{i_k}{\frac{x_i}{r}}\)=2_{n-2}C_{{\frac{n}{2}}-1}\sum\limits^n_{i=1}f(x_i),$ then f : X ${\rightarrow}$ Y is additive, where $r{\in}R$. We also prove the stability in normed group by using shadowing property and the Hyers-Ulam stability of the functional equation in Banach spaces and in Banach modules over unital C-algebras. As an application, we show that every almost linear bijection h : A ${\rightarrow}$ B of unital $C^*$-algebras A and B is a $C^*$-algebra isomorphism when $h(\frac{2^s}{r^s}uy)=h(\frac{2^s}{r^s}u)h(y)$ for all unitaries u ${\in}$ A, all y ${\in}$ A, and s = 0, 1, 2,....

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.421-424
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• 2004

This paper presents a sufficient condition for the real weighted diamond polynomials to be Schur stable using bilinear transformation and Kharitonov's theorem.

• Journal of the Chungcheong Mathematical Society
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• v.21 no.3
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• pp.395-401
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• 2008

In this paper we investigate h-stability for linear dynamic equations on time scales under $u_{\infty}$-similarity.

• Journal of the Chungcheong Mathematical Society
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• v.21 no.1
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• pp.91-97
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• 2008

We study h-stability for linear differential systems by using $t_{\infty}$-quasisimilarity and Gronwall's inequality.

• Journal of the Chungcheong Mathematical Society
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• v.21 no.2
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• pp.189-196
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• 2008

In this paper, we study h-stability for linear difference systems by using the notion of $n_{\infty}$-quasisimilarity and discrete Gronwall's inequality.

• Journal of the Chungcheong Mathematical Society
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• v.3 no.1
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• pp.83-88
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• 1990

It is well-known that under suitable conditions, uniform asymptotic stability implies total stability. We prove this theorem of Malkin by using Liapunov-like functions and so our proof is a detailed version of Yoshizawa's proof.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.4
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• pp.935-943
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• 2011

We study the h-stability for linear impulsive differential equations and their perturbations by using the impulsive integral inequalities.

• East Asian mathematical journal
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• v.35 no.3
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• pp.331-340
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• 2019

In this paper, we investigate the stability for the functional equation $f(x+ky)-kf(x+y)+kf(x-y)-f(x-ky)-(k^3-k)f(y)+(k^3-k)f(-y)=0$ in the sense of M. S. Moslehian and Th. M. Rassias.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.202-208
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• 2005

In Korea it tends to rely on foreign standards for the stability management of the embankment slope on the soft clay layer. The Matsuo-Kawamura's method, the Kurihara's method, the Tominaga- Hashimoto's method and the Shibata-Sekiguchi's method are generally employed at site. In this study these slope stability methods are investigated and the applicability of the stability management methods is evaluated through numerical analysis. It is evaluated that stability is overestimated to some degree by the Matsuo-Kawamura method. According to the result by the Tominaga-Hashimoto method there is some risk of sudden failure. This implies that the careful attention is necessary for the management of monitoring the field data. Even though the stability tends to be underestimated by the Kurihara's method, however, it is estimated that this method is applicable to the field when the probable uncertainty at site is considered. For the Shibata-Sekiguchi's method, there is some difficulties in determining the failure index for the practical application, it is considered as safe when the existing estimated failure index is greater than ${\Delta}_q/{\Delta}{\delta}$. In this study, however, it is evaluated to be safe as well when ${\Delta}_q/{\Delta}{\delta}$ to load shows the tendency of constant increase.