• The Korean Journal of Ceramics
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• 제4권2호
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• pp.78-82
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• 1998

The oxygen nonstoichiometry (x) of UO$_{2+x}$ and $(Ce_yU_{1-y})O_{2+x}$ (y=0.05, 0.25) has been measured as a function of oxygen activity (a02) at 100$0^{\circ}C$ by a solid state coulometri titration technique. The results for UO$_{2+x}$ are in a good agreement with literature data and the ao2-dependence of the nonstoichimetry has been well explained with (2:2:2) cluster model. The equilibrium oxygen activity of $(Ce_yU_{1-y})O_{2+x}$ increases with Ce-content (y) for given nonstoichiometry (x), which is ascribed to the fact that Ce is present as Ce$^{3+}\; and\; Ce^{4+}$, and, therefore, the addition of Ce reduces the oxidation capacity of UO$_{2+x}$. From the oxygen activity dependence of x in $(Ce_yU_{1-y})O_{2+x}$ the defect structure of $(Ce_yU_{1-y})O_{2+x}$ is discussed.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3597-3601
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• 2013

The reactions of bis(Y-aryl) chlorothiophosphates (1) with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The Hammett plots for substituent Y variations in the substrates show biphasic concave upwards with a break point at Y = H. The cross-interaction constants (${\rho}_{XY}$) are positive for both electron-donating and electron-withdrawing Y substituents. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorothiophosphates (2). The cross-interaction between Y and Y, due to additional substituent Y, is significant enough to result in the change of the sign of ${\rho}_{XY}$ from negative with 2 to positive with 1. The effect of the cross-interaction between Y and Y on the rate changes from negative role with electron-donating Y substituents to positive role with electron-withdrawing Y substituents, resulting in biphasic concave upward free energy correlation with Y. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate involving a predominant frontside attack hydrogen bonded, four-center-type transition state is proposed based on the positive sign of ${\rho}_{XY}$ and primary normal deuterium kinetic isotope effects.

• 생약학회지
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• 제30권1호
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• pp.12-17
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• 1999

The youngkaechulgamtang (Y) composed of four herb drugs, including Hoelen (H). Cinnamomi Ramulus (C). Atractylodis Rhizoma Alba (A) and Glycyrrhizae Radix (G). In oriental medicine literatures, Youngkaechulgamtang is described to be effective in headache, inflammation, uremia, gastritis, diarrhea and hypertension. To estimate the clinical effectiveness of Youngkaechulgamtang, several pharmacological experiments were carried out. The results are summerized as follows; On acetaminophen-induced hepatotoxicity, C+A, Y-G, Y-H, MIX and Y showed the significant elevation of glutathione-S-transferase. But, C+A, Y-G, Y-H, MIX and Y showed the significant suppression of serum aminotransferases. On ANIT-induced cholestasis, U (Ursodesoxycholic acid 50 mg/kg)+$Y_l$ (760 mg/kg) showed the significant increase of bile juice volume. $Y_l,\;Y_2$ (1520 mg/kg), U, $U+Y_l$ showed the remarkable increase of cholic acid. U and $U+Y_l$ showed the significant decrease of total bilirubin. From these results, it is suggest that Y shows liver protective effect against various hepatic injury. Especially, Youngkaechulgamtang was more effective than mixture of 4 ingredients in the elevation of glutathione-S-transferase in acetaminophen-induced hepatotoxicity.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.535-539
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• 2007

Given operators X and Y acting on a separable complex Hilbert space $\mathcal{H}$, an interpolating operator is a bounded operator A such that AX=Y. In this article, we show the following: Let $Alg\mathcal{L}$ be a tridiagonal algebra on a separable complex Hilbert space $\mathcal{H}$ and let $X=(x_{ij})\;and\;Y=(y_{ij})$ be operators in $\mathcal{H}$. Then the following are equivalent: (1) There exists a normal operator $A=(a_{ij})\;in\;Alg\mathcal{L}$ such that AX=Y. (2) There is a bounded sequence $\{\alpha_n\}\;in\;\mathbb{C}$ such that $y_{ij}=\alpha_jx_{ij}\;for\;i,\;j\;{\in}\;\mathbb{N}$. Given vectors x and y in a separable complex Hilbert space $\mathcal{H}$, an interpolating operator is a bounded operator A such that Ax=y. We show the following: Let $Alg\mathcal{L}$ be a tridiagonal algebra on a separable complex Hilbert space $\mathcal{H}$ and let $x=(x_i)\;and\;y=(y_i)$ be vectors in $\mathcal{H}$. Then the following are equivalent: (1) There exists a normal operator $A=(a_{ij})\;in\;Alg\mathcal{L}$ such that Ax=y. (2) There is a bounded sequence $\{\alpha_n\}$ in $\mathbb{C}$ such that $y_i=\alpha_ix_i\;for\;i{\in}\mathbb{N}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
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• pp.3-6
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• 1988

Electrical and magnetic properties of $Y_1Ba_2Cu_3O_7-y$ sintered with $Bi_2O_3$ have been investigated by levitation experiment and the measurement of electrical resistivity. The effects of $Bi_2O_3$ addition on the microstructure of the sintered specimens were also investigated. The electrical resistivity in the normal state is smaller in $Y_{0.85}Bi_{0.15}Ba_2Cu_3O_{7-y}$, where the Bi is substituted into Y site, than in the basic compound $Y_1Ba_2Cu_3O_{7-y}$ due to improved microstructure. On the other hand, the microstructure is poor and electrical resistivity is larger in the $Y_1Ba_2Cu_3O_{7-y}$ sintered with excess $Bi_2O_3$. It appears that the impurity in grain boundary affect the electrical properties significantly but has little effect on the magnetic property.

• 대한화학회지
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• 제21권6호
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• pp.422-426
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• 1977

Zeolite Y를 합성하여 Co, Ni 및 Pd 이온으로 이온교환하고 수소기류중에서 환원함으로서 전이금속-Zeolite Y 촉매를 얻었다. 이들 Co-, Ni-, Pd-Y와 La-이온교환한 Y(LaY) 촉매에서의 1-butene 및 n-butane의 분해반응을 micro-catalytic pulse 방법으로 연구하였다. 1-Butene 분해반응에 있어서는 Ni-, Co-, Pd-Y 및 LaY 모두 높은 활성을 보여주었고 1-butene 분해반응에 대한 활성은 촉매상의 금속성분과는 큰 관계없이 산성 성분만이 주로 관련되고 있는것 같다. LaY에서는 $400^{\circ}C$에서 n-butane 분해반응에 대한 활성을 나타내지 않았으나 소량의 1-butene을 가함으로써 분해반응이 촉진되었다. Ni- 및 Pd-zeolite Y에서는 n-butane의 분해반응이 현저하게 일어났다. 분해반응에 대해서는 수소에 의한 환원온도가 높고 또 금속성분 함량이 많은 것이 활성이 높았다. n-butane 분해반응에 있어서는 금속성분에서의 butene으로의 탈수소반응이 첫 단계인 것으로 본다. Ni-Y에서는 1-butene과 수소 혼합반응물 및 n-butane의 분해생성물이 모두다 C_1$뿐이었다. n-butane은 Ni-Y에서는 butene으로 탈수소되고 이어서 C_1$으로 hydrocracking 되는 반응과정을 밟고 있다고 본다.

• Korean Journal of Mathematics
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• 제18권3호
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• pp.311-322
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• 2010

In this paper, we prove stabilities of the reciprocal difference functional equation $$r(\frac{x+y+z}{3})-r(x+y+z)=\frac{2r(x)r(y)r(z)}{r(x)r(y)+r(y)r(z)+r(z)r(x)}$$ and the reciprocal adjoint functional equation $$r(\frac{x+y+z}{3})+r(x+y+z)=\frac{4r(x)r(y)r(z)}{r(x)r(y)+r(y)r(z)+r(z)r(x)}$$ with three variables. Stabilities of the reciprocal difference functional equation and the reciprocal adjoint functional equation in two variables was proved by K. Ravi, J. M. Rassias and B. V. Senthil Kumar. We extend their results to three variables in similar types.

• 한국세라믹학회지
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• 제38권1호
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• pp.56-60
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• 2001

90.24 mol% ZrO$_2$-5.31 mol% $Y_2$O$_3$-4.45 mol% Nb$_2$O$_{5}$ 조성의 (Y,Nb)-TZP와 (Y,Nb)-TZP/Al$_2$O$_3$복합체를 155$0^{\circ}C$~1$600^{\circ}C$에서 1~2시간 소결하여 제조하였다. 시편의 결함에 대한 저항성을 조사하기 위하여 R-curve, Weibull modulus, slow crack growth 변수 등을 조사하였다. 실험결과, (Y,Nb)-TZP와 (Y,Nb)-TZP/Al$_2$O$_3$복합체 모두 상용 3Y-TZP 보다 우수한 결함 저항성이 관찰되었다. (Y,Nb)-TZP/Al$_2$O$_3$복합체의 결함 저항성은 $Al_2$O$_3$첨가에 의한 결정립 가교 인화, 분산강화, R-curve 효과에 의한 것으로 추정된다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제27권1호
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• pp.25-33
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• 2020

In this paper, we consider the following quadratic (ρ₁, ρ₂)-functional equation (0, 1) $$N(2f({\frac{x+y}{2}})+2f({\frac{x-y}{2}})-f(x)-f(y)-{\rho}_1(f(x+y)+f(x-y)-2f(x)-2f(y))-{\rho}_2(4f({\frac{x+y}{2}})+f(x-y)-f(x)-f(y)),t){\geq}{\frac{t}{t+{\varphi}(x,y)}}$$, where ρ₂ are fixed nonzero real numbers with ρ₂ ≠ 1 and 2ρ₁ + 2ρ₂≠ 1, in fuzzy normed spaces. Using the fixed point method, we prove the Hyers-Ulam stability of the quadratic (ρ₁, ρ₂)-functional equation (0.1) in fuzzy Banach spaces.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1095-1096
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• 2006

When $Y_2O_3$ was added to Ti-excess $BaTiO_3$ ((Ba+Y)/Ti =1), the area occupied by $Y^{3+}$ ion was confirmed by its microstructure development, electrical conductivity behavior and lattice constant. Grain growth inhibition was observed when the content of donor dopant exceeded a critical value ($x{\approx}.0.01$) in $BaTiO_3+x(0.5Y_2O_3+TiO_2)$ system. A donor-doped behavior was observed at various Y contents ($0.2\sim3.0$ mol% Y) when $Y_2O_3$ was added to $TiO_2$-excess $BaTiO_3$. As Y content was increased, (002) and (200) peaks shifted to higher angles and the lattice constant (a and c axis) decreased gradually.