• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.555-558
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• 2000

Layered perovskite La$_{2-x}$Ca$_{l-x}$Mn$_2$O$_{7}$ phases were synthesized by solid state reaction. Single phase R-P could be obtained in the range of 0.4$_{2-x}$Ca$_{l-x}$Mn$_2$O$_{7}$. About 30% of MR ratio was obtained at 270K when 5 T of magnetic field was applied.ied.ied.ied.

• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.437-448
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• 2007

Suppose K is a nonempty closed convex nonexpansive retract of a real uniformly convex Banach space E with P as a nonexpansive retraction. Let $T_1,\;T_2\;and\;T_3\;:\;K{\rightarrow}E$ be nonexpansive mappings with nonempty common fixed points set. Let $\{\alpha_n\},\;\{\beta_n\},\;\{\gamma_n\},\;\{\alpha'_n\},\;\{\beta'_n\},\;\{\gamma'_n\},\;\{\alpha'_n\},\;\{\beta'_n\}\;and\;\{\gamma'_n\}$ be real sequences in [0, 1] such that ${\alpha}_n+{\beta}_n+{\gamma}_n={\alpha}'_n+{\beta'_n+\gamma}'_n={\alpha}'_n+{\beta}'_n+{\gamma}'_n=1$, starting from arbitrary $x_1{\in}K$, define the sequence $\{x_n\}$ by $$\{zn=P({\alpha}'_nT_1x_n+{\beta}'_nx_n+{\gamma}'_nw_n)\;yn=P({\alpha}'_nT_2z_n+{\beta}'_nx_n+{\gamma}'_nv_n)\;x_{n+1}=P({\alpha}_nT_3y_n+{\beta}_nx_n+{\gamma}_nu_n)$$ with the restrictions $\sum^\infty_{n=1}{\gamma}_n<\infty,\;\sum^\infty_{n=1}{\gamma}'_n<\infty,\; \sum^\infty_{n=1}{\gamma}'_n<\infty$. (i) If the dual $E^*$ of E has the Kadec-Klee property, then weak convergence of a $\{x_n\}$ to some $x^*{\in}F(T_1){\cap}{F}(T_2){\cap}(T_3)$ is proved; (ii) If $T_1,\;T_2\;and\;T_3$ satisfy condition(A'), then strong convergence of $\{x_n\}$ to some $x^*{\in}F(T_1){\cap}{F}(T_2){\cap}(T_3)$ is obtained.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1236-1242
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• 2007

Sixty healthy growing pigs ($Duroc{\times}Landrace{\times}Yorkshire$ with an average BW of 21.4 kg) were used to determine the true digestible phosphorus (TDP) requirement of growing pigs on the basis of growth performance and serum biochemical indices. Pigs were assigned randomly to one of five dietary treatments (12 pigs/diet), representing five levels of TDP (0.16%, 0.20%, 0.23%, 0.26% and 0.39%). There were three replications per treatment, with four pigs (2 barrows and 2 gilts) in each replication (2 pigs/pen) A randomized-block design was used, with pen as the experimental unit. Experimental diets were formulated to provide the 5 TDP levels with a total calcium (Ca) to TDP ratio of 2:1, and offered to pigs at 5% BW for 28 d. The total Ca contents of the five diets were 0.33, 0.38, 0.45, 0.51 and 0.79%, respectively. During the 28-d experimental period, the ADG of pigs was affected by dietary TDP levels as described by Equation 1: y = $-809,532x^4+788,079x^3-276,250x^2+42,114x-1$,759; ($R^2$ = 0.99; p<0.01; y = ADG, g/d; x = dietary TDP, %). The feed:gain ratio for pigs was affected by dietary TDP levels as described by Equation 2: y = $3,651.1x^4-3,480.4x^3+1,183.8x^2-172.5x+10.9$ ($R^2$ = 0.99; p<0.01; y = feed:gain ratio; x = dietary TDP, %). Total P concentrations in serum were affected by dietary TDP levels as described by Equation 3: y = $-3,311.7x^4+3,342.7x^3-1,224.6x^2+195.6x-8.7$ ($R^2$ = 0.99; p<0.01; y = total serum P concentration and x = dietary TDP, %). The highest ADG (782 g/d), the lowest feed:gain ratio (1.07), and the highest total serum P concentration (3.1 mmol/L) were obtained when dietary TDP level was 0.34%. Collectively, these results indicate that the optimal TDP requirement of growing pigs is 0.34% of the diet (e.g., 5.1 g/day for a 30-kg pig that consumed 1.5 kg feed daily) at a total Ca to TDP ratio of 2:1.

• Kyungpook Mathematical Journal
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• v.50 no.1
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• pp.153-164
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• 2010

We study the global asymptotic stability, the character of the semicycles, the periodic nature and oscillation of the positive solutions of the difference equation $x_{n+1}=\frac{p+x_{n-k}}{q+x_n}+\frac{x_{n-k}}{x_n}$, n=0, 1, 2, ${\cdots}$. where p, q ${\in}$ (0, ${\infty}$), q ${\neq}$ 2, k ${\in}$ {1, 2, ${\cdots}$} and the initial values $x_{-k}$, ${\cdots}$, $x_0$ are arbitrary positive real numbers.

• Honam Mathematical Journal
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• v.31 no.2
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• pp.233-237
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• 2009

In this paper, we show that: (1) every strongly ${\omega}$-monolithic space X with countable fan-tightness is Fr$\'{e}$chet-Urysohn; (2) a direct proof of that X is Lindel$\"{o}$f when $C_p$(X) is Fr$\'{e}$chet-Urysohn; and (3) X is Lindel$\"{o}$f when X is paraLindel$\"{o}$f and $C_p$(X) is AP. (3) is a generalization of the result of [8]. And we give two questions related to Fr$\'{e}$chet-Urysohn and AP properties on $C_p$(X).

• Communications of the Korean Mathematical Society
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• v.35 no.4
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• pp.1299-1307
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• 2020

We show that the Liechti-Strenner's example for the closed nonorientable surface in [13] minimizes the dilatation within the class of pseudo-Anosov homeomorphisms with an orientable invariant foliation and all but the first coefficient of the characteristic polynomial of the action induced on the first cohomology nonpositive. We also show that the Liechti-Strenner's example of orientation-reversing homeomorphism for the closed orientable surface in [13] minimizes the dilatation within the class of pseudo-Anosov homeomorphisms with an orientable invariant foliation and all but the first coefficient of the characteristic polynomial p(x) of the action induced on the first cohomology nonpositive or all but the first coefficient of p(x)(x ± 1)², p(x)(x² ± 1), or p(x)(x² ± x + 1) nonpositive.

• Bulletin of the Korean Mathematical Society
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• v.55 no.4
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• pp.1209-1219
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• 2018

We provide a direct proof of the following theorem of Kalton, Hollenbeck, and Verbitsky [7]: let H be the Hilbert transform and let a, b be real constants. Then for 1 < p < ${\infty}$ the norm of the operator aI + bH from $L^p(\mathbb{R})$ to $L^p(\mathbb{R})$ is equal to $$\({\max_{x{\in}{\mathbb{R}}}}{\frac{{\mid}ax-b+(bx+a){\tan}{\frac{\pi}{2p}}{\mid}^p+{\mid}ax-b-(bx+a){\tan}{\frac{\pi}{2p}}{\mid}^p}{{\mid}x+{\tan}{\frac{\pi}{2p}}{\mid}^p+{\mid}x-{\tan}{\frac{\pi}{2p}}{\mid}^p}}\)^{\frac{1}{p}}$$. Our proof avoids passing through the analogous result for the conjugate function on the circle, as in [7], and is given directly on the line. We also provide new approximate extremals for aI + bH in the case p > 2.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.229-234
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• 2005

The boundedness, global attractivity, oscillatory and asymptotic periodicity of the positive solutions of the difference equation of the form $x_{n+l} =\alpha+\frac{x_{n-1}^{p}}{x_{n}^{p}},\;\; n = 0, 1, ...$ is investigated, where all the coefficients are nonnegative real numbers.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2003.07a
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• pp.84-84
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• 2003

고분자 키토산(분자량 약 800,000)을 농도별(0%, 0.1%, 0.2%, 0.3%)로 김치를 제조하여, pH, 적정산도, 총균수, 젖산균 수, 대장균군 수 및 관능검사를 조사한 결과는 다음과 같이 나타났다. 1. 키토산 무첨가 김치는 발효 후 6일경에 pH가 초기 5.4에서 4.1로 급격히 떨어졌으며 그 후부터는 천천히 떨어져 발효 후 약 15일 경과 후에는 3.9로 나타났다. 그러나 0.1%, 0.2% 및 0.3% 고분자 키토산을 첨가한 김치에서는 초기 pH 5.38, 5.30 및 5.28에서 6일경에는 pH가 0.1%, 0.2% 및 0.3% 고분자 키토산에서 4.23, 4.34 및 4.47로 각각 나타났다. 15일 경과 후에는 0.1% 고분자 키토산 김치는 키토산 무첨가 김치와 거의 같은 pH인 3.9로 나타났으나 0.2%와 0.3% 고분자 키토산 김치의 pH는 3.90보다 높은 4.10, 4.10으로 각각 나타났다. 2. 각 김치 종류별 적정산도를 측정한 결과는 발효초기에 모든 구가 0.72%로 나타났으며, 발효 후 6일 경에서는 키토산 무첨가, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 적정산도는 각각 2.16%, 2.00%, 1.70% 및 1.30%로 나타났다. 그리고 15일 경과 후에는 키토산 무첨가 김치의 적정산도가 2.25%이였으나 0.1%, 0.2% 및 0.3% 고분자 키토산 김치는 각각 2.26%, 2.24 및 2.22%로 나타났다. 3. 발효가 진행 중에 총균수를 측정한 결과 시간과 더불어 총균수가 모든 구에 있어서 서서히 증가하였고 발효초기의 모든 김치구의 총균수는 2.5X105∼5.4X106 cfu/g 범위였으며, 김치 맛이 들기 시작한 6일경에서의 각 구별 총균수는 키토산 무첨가 김치가 2.4X109 cfu/g이였구 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 총균수는 각각 1.2X109 cfu/g, 4.0X108 cfu/g 및 1.1X107 cfu/g으로 나타났다. 그리고 김치가 완전히 익은 15일 후에는 무첨가 김치, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 총균수는 5.4X107 cfu/g, 3.3X107 cfu/g, 1.8X108cfu/g 및 4.2X108 cfu/g로 나타났다. 4. 발효가 진행 중에 젖산균 수를 측정한 결과 시간과 더불어 젖산균 수가 모든 구에 있어서 서서히 증가하였으며, 발효초기의 모든 김치구의 젖산균 수는 2.0X104∼2.7X106 cfu/g 범위였으며 김치 맛이 들기 시작한 6일경에서의 각 구별 젖산균 수는 키토산 무첨가 김치가 3.2X108 cfu/g이었고, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 젖산균 수는 각각 1.6X108 cfu/g, 13X108 cfu/g 및 9.6X107 cfu/g으로 나타났다. 그리고 김치가 완전히 익은 15일 후에는 무첨가 김치, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 젖산균 수는 5.4X107 cfu/g, 3.3X107 cfu/g, 8.6X106 cfu/g 및 2.6X106 cfu/g로 나타났다. 5. 발효가 진행 중에 대장균 군 수가 시간과 더불어 대장균군 수가 모든 구에 있어서 6일까지는 서서히 증가하다가 그 후부터는 대장균 군 수가 감소하였다. 즉, 발효초기에는 모든 구가 2.0X104∼4.0X105 cfu/g이었고, 6일 경에는 8.9X104∼4.5X105 cfu/g로 약간 증가하였으며 15일후에는 키토산 무첨가 김치가 2.0X102 cfu/g이었으며, 0.1%, 0.2% 및 0.3% 고분자 키토산 김치의 대장균군 수는 각각 2.0X102 cfu/g, 1.1X102 cfu/g 및 4.0X101 cfu/g로 점점 감소하였다. 6. 관능검사 결과는 키토산 무첨가 김치와 0.1% 첨가 김치는 유사한 선호도를 나타내어 0.1% 첨가 김치가 기능성과 보존성을 높여줄 뿐만 아니라 선호도도 높은 것으로 나타났다.

• Journal of applied mathematics & informatics
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• v.20 no.1_2
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• pp.75-96
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• 2006

Let m, n be positive integers. We denote by R(m,n) (respectively P(m,n)) the class of all groups G such that, for every n subsets $X_1,X_2\ldots,X_n$, of size m of G there exits a non-identity permutation $\sigma$ such that $X_1X_2{\cdots}X_n{\cap}X_{\sigma(1)}X_{/sigma(2)}{\cdots}X_{/sigma(n)}\neq\phi$ (respectively $X_1X_2{\cdots}X_n=X_{/sigma(1)}X_{\sigma(2)}{\cdots}X_{\sigma(n)}$). Let G be a non-abelian group. In this paper we prove that (i) $G{\in}P$(2,3) if and only if G isomorphic to $S_3$, where $S_n$ is the symmetric group on n letters. (ii) $G{\in}R$(2, 2) if and only if ${\mid}G{\mid}\geq8$. (iii) If G is finite, then $G{\in}R$(3, 2) if and only if ${\mid}G{\mid}\geq14$ or G is isomorphic to one of the following: SmallGroup(16, i), $i\in$ {3, 4, 6, 11, 12, 13}, SmallGroup(32, 49), SmallGroup(32, 50), where SmallGroup(m, n) is the nth group of order m in the GAP [13] library.