• Structural Engineering and Mechanics
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• v.43 no.3
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• pp.311-320
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• 2012

The higher-order asymptotic C(t) - $A_2(t)$ approach was employed to investigate the crack-tip stress of two collinear cracks in a power-law creeping material under the plane strain conditions. A comprehensive calculation was made of the single crack, collinear crack model with S/a = 0.4 and 0.8, by using the C(t) - $A_2(t)$ approach, HRR-type field and the finite element analysis; the latter two methods were used to check the constraint significance and the calculation accuracy of the C(t) - $A_2(t)$ approach, respectively. With increasing the creep time, the constraint $A_2$ was exponentially increased in the small-scale creep stage, while no discernible dependency of the constraint $A_2$ on the creep time was found at the extensive creep state. In addition, the creep time and the mechanical loads have no distinct influence on accuracy of the results obtained from the higher-order asymptotic C(t) - $A_2(t)$ approach. In comparison with the HRR-type field, the higher-order asymptotic C(t) - $A_2(t)$ solution matches well with the finite element results for the collinear crack model.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.1
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• pp.113-119
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• 2011

Let T be a bounded linear operator on a complex Hilbert space $\mathcal{H}$. An operator T is called class A operator if ${\left|{T^2}\right|}{\geq}{\left|{T^2}\right|}$ and is called class A(k) operator if $({T^*\left|T\right|^{2k}T})^{\frac{1}{k+1}}{\geq}{\left|T\right|}^2$. In this paper, we show that ${\sigma}$ is continuous when restricted to the set of class A operators and consider the tensor products of class A(k) operators.

• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.599-612
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• 2010

This study was conducted to investigate the effect of organic feed containing rice bran and soybean hull as organic by-products on milk production of mid-lactation dairy goats. Four Saanen dairy goats (initial BW $59.4{\pm}7.4$ kg, average 6 lactation months, fourth kidding) were allocated into conventional feed group (T1) and organic feed group (T2) with 2${\times}$3 crossover design for 9 weeks. Experimental diets were formulated to contain 23 MJ ME/d, 382 g CP/d DM based on NRC (1981) and AFRC (1998). Dry matter (DM) intakes of concentrate and silage were higher in T2 (1,232 and 96 g/d) than T1 (1,105 and 91 g/d) (p<0.05). However, DM intake of hay was higher in T1 (488 g) than T2 (347 g) (p<0.05). Total DM intake had no significant difference between T1 and T2. Although no significant difference was found in milk yield between treatments, T2 numerically increased (+150 g/d) compared with T1. There were no significant differences in milk composition and milk urea nitrogen (MUN) between T1 and T2. Relative to T1, T2 significantly increased the stearic acid (C18:0) and linoleic acid (C18:2) (p<0.05). Overall results of the present experiment indicated that organic feed could not adversely affect DM intake and milk production in dairy goats compared with conventional feed.

• Journal of the Chungcheong Mathematical Society
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• v.30 no.3
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• pp.291-304
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• 2017

This paper shows that the solutions to the perturbed differential system $$y^{\prime}=f(t,y)+{{\displaystyle\smashmargin{2}{\int\nolimits_{t_0}}^{t}}g(s,y(s),T_1y(s))ds+h(t,y(t),T_2y(t))$$, have bounded properties by imposing conditions on the perturbed part ${\int}_{t_0}^{t}g(s,y(s),T_1y(s))ds,h(t,y(t),T_2y(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.377-392
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• 2008

Let X be a real reflexive Banach space with a uniformly $G\hat{a}teaux$ differentiable norm, C a nonempty closed convex subset of X, T : C $\rightarrow$ X a continuous pseudocontractive mapping, and A : C $\rightarrow$ C a continuous strongly pseudocontractive mapping. We show the existence of a path ${x_t}$ satisfying $x_t=tAx_t+(1- t)Tx_t$, t $\in$ (0,1) and prove that ${x_t}$ converges strongly to a fixed point of T, which solves the variational inequality involving the mapping A. As an application, we give strong convergence of the path ${x_t}$ defined by $x_t=tAx_t+(1-t)(2I-T)x_t$ to a fixed point of firmly pseudocontractive mapping T.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.818-822
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• 1999

Background: Thoracoscopic T2 sympathicotomy had been performed as a simple and effective method in treating palmar hyperhidrosis, however, this method had the complications of compensatory hyperhidrosis and facial anhidrosis. Therefore, a more limited and modified methods for T2 sympathicotomies were introduced and comparative analysis of the modified upper and lower T2 sympathicotomy were made in the treatment of palmar hyperhidrosis. Material and Method: From January 1997 to December 1998, 41 patients with palmar hyperhidrosis had been treated by modified T2 sympathicotomy at the Kon-Kuk University Seoul Hospital. Twenty-four patients underwent a modified upper T2 sympathicotomy(Group A), and seventeen patients underwent a modified lower sympathicotomy(Group B). A comparison between groups A and B were made according to the medical records and interview results. Result: All patients showed symptomatic improvements after the operation. The anisocoria, facial anhidrosis and dissatisfaction for compensatory hyperhidrosis were more common in Group A and the individual satisfaction for the operations were higher in Group B. Conclusion: The modified lower T2 sympathicotomy might be a more effective and less complicated method than the modified upper T2 sympathicotomy.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.223-234
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• 2007

This study was done to determine the trans fatty acid (tFA) composition of human milk from postpartum to sixth months after delivery, to investigate the tFA intake of lactating women, and to estimate the intakes of tFA by infants exclusively fed breast milk. A total of 27 lactating Korean women participated to this study voluntarily, gave their breast milk, and responded to an investigation of their diets. The lactating women consumed 2.3-2.8 g/d of tFAs over the period of the first, second, third, and sixth months postpartum, which was 3.4-4.9% of the total fat intake and 0.8%-1.2% of the total energy intake. The proportions of tFAs in the breast milk were 1.89% in colostrum, 1.78% in transitional milk, and 1.78-2.25 in mature milk of the first, second, third, and sixth months postpartum. The tFAs of the breast milk identified in this study were C16:1n9t, C18:1n9t, C18:2n6t12t, C18:2n6t12c, C18:2n6t12t and C18:2n6t11t. Among them, C18:1n9t was predominant, which made up 59.26% of all tFAs in cob strum, 62.36% in transitional milk, and 64.42% in mature milk. The proportion of total tFA was unchanged with time, although some significant differences were noted for individual tFAs. The percentages of C18:2n6t12c and C18:2n6c12t decreased over the study period. Estimated tFA intake of the exclusively breast-fed infants was 0.18 g/d when fed colostrum, 0.29 g/d when fed transitional milk, and 0.53 g/d when fed mature milk until the sixth month of postpartum. Those were 0.5%, 0.8%, and 1.1% of the total energy intake. The results in this study indicate that lactating Korean women consume not a large quantity of tFAs, secrete breast milk not containing much tFA, and the estimated intake of tFAs by infants fed exclusively breast milk is not great.

• Communications of the Korean Mathematical Society
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• v.19 no.2
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• pp.307-319
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• 2004

In this paper, we establish some new oscillation criteria for the functional differential equations of the form $\frac{d}{dt}$$\frac{1}{a_{n-1}(t)}$$\frac{d}{dt}(\frac{1}{{a_{n-2}(t)}\frac{d}{dt}(...(\frac{1}{a_1(t)}\frac{d}{dt}x(t))...)))^\alpha$ + $\delta[f_1(t,s[g_1(t)],\frac{d}{dt}x[h_1(t)])$ + $f_2(t,x[g_2(t)],\frac{d}{dt}x[h_2(t)])]=0$ via comparing it with some other functional differential equations whose oscillatory behavior is known.

• Kyungpook Mathematical Journal
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• v.54 no.3
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• pp.387-399
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• 2014

We show that in quasi-topological spaces, separation axiom $T_2$ is equivalent to ${\alpha}-T_2$, $T_0$ is equivalent to semi - $T_0$, and semi - $T_{\frac{1}{2}}$ is equivalent to semi - $T_D$. Also, we give characterizations for ${\alpha}-T_1$, semi - $T_1$ and semi - $T_{\frac{1}{2}}$ generalized topological spaces.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.1
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• pp.56-62
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• 1992

The GaAs bulk crystals are grown by the Synthesis Solute Diffusion(SSD) method and its properties are investigated. The crystal growth rate at optimum condition is 0.28 cm/day and their temperature dependence is R(T) = 2.92 x 10S04T exp(-1.548eV/kS1BTT) [cmS02T/day.K]. Etch pits density distribution along radial direction is order of 10S04TcmS0-2T and 10S03TcmS0-2T at the edge and middle of the wafers, respectively, and it increased exponentially along vertical direction of ingot. Moreover,it is uniformly distributed as order of 10S03TcmS0-2T in radial direction of In doped GaAs. The carrier concentration and mobilities are measured to 0.34-2.1 x 10S016T cmS0-3T and 2.3-3.3x10S03T cmS02T/V.sec, respectively.