• 대한수학회논문집
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• 제27권3호
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• pp.441-448
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• 2012

Let R be a prime ring with center Z and characteristic different from two, U a nonzero Lie ideal of R such that $u^2{\in}U$ for all $u{\in}U$ and $d$ be a nonzero (${\sigma}$, ${\tau}$)-derivation of R. We prove the following results: (i) If $[d(u),u]_{{\sigma},{\tau}}$ = 0 or $[d(u),u]_{{\sigma},{\tau}}{\in}C_{{\sigma},{\tau}}$ for all $u{\in}U$, then $U{\subseteq}Z$. (ii) If $a{\in}R$ and $[d(u),a]_{{\sigma},{\tau}}$ = 0 for all $u{\in}U$, then $U{\subseteq}Z$ or $a{\in}Z$. (iii) If $d([u,v])={\pm}[u,v]_{{\sigma},{\tau}}$ for all $u{\in}U$, then $U{\subseteq}Z$.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1675-1680
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• 2011

Inductive power transfer module(IPTM) is a contact-less power supply device and its application range has been extended to the large capacity devices such as electric vehicles, industrial mover and railway system as well as small capacity devices such as electric toothbrush charger, celluar phone charger, and so on. For railway application, the IPTM will transfer energy while train stops at a station for around 30[sec]. Therefore, equivalent circuit parameters and coupling coefficient of IPTM are an important design factor for the high energy transfer efficiency. This paper investigates the properties of equivalent circuit parameters and coupling coefficient of U-U type IPTM and U-I type IPTM using an analytical method and experimental method. Considering the coupling coefficient of the U-U type is larger than U-I type's, the U-U type is suitable for an application which need maximum power transfer and high efficiency.

• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.63-72
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• 2008

As a part of abating formaldehyde emission of urea-formaldehyde (UF) resin adhesive, this study was conducted to investigate chemical structures of UF resin adhesives with different formaldehyde/urea (F/U) mole ratios, using carbon-13 nuclear magnetic resonance ($^{13}C$-NMR) spectroscopy. UF resin adhesives were synthesized at four different F/U mole ratios such as 1.6, 1.4, 1.2, and 1.0 for the analysis. The analysis $^{13}C$-NMR spectroscopy showed that UF resin adhesives with higher F/U mole ratios (i.e., 1.6 and 1.4) had two distinctive peaks, indicating the presence of dimethylene ether linkages and methylene glycols, a dissolved form of free formaldehyde. But, these peaks were not detected at the UF resins with lower F/U mole ratios (i.e., 1.2 and 1.0). These chemical structures present at the UF resins with higher F/U mole ratios indicated that UF resin adhesive with higher F/U mole ratio had a greater contribution to the formaldehyde emission than that of lower F/U mole ratio. Uronic species were detected for all UF resins regardless of F/U mole ratios.

• Journal of applied mathematics & informatics
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• 제35권5_6호
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• pp.551-563
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• 2017

In this paper, by using fixed point theorems in cones, the existence of positive solutions is considered for nonlinear m-point boundary value problem for the following second-order dynamic equations on time scales $$u^{{\Delta}{\nabla}}(t)+a(t)f(t,u(t))=0,\;t{\in}(0,T),\;{\beta}u(0)-{\gamma}u^{\Delta}(0)=0,\;u(T)={\sum_{i=1}^{m-2}}\;a_iu({\xi}_i),\;m{\geq}3$$, where $a(t){\in}C_{ld}((0,T),\;[0,+{\infty}))$, $f{\in}C([0,T]{\times}[0,+{\infty}),\;(-{\infty},+{\infty}))$, the nonlinear term f is allowed to change sign. We obtain several existence theorems of positive solutions for the above boundary value problems. In particular, our criteria generalize and improve some known results [15] and the obtained conditions are different from related literature [14]. As an application, an example to demonstrate our results is given.

• 무역상무연구
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• 제18권
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• pp.7-25
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• 2002

Owing to a tremendous progress of information technology we have faced a great change of a society. This change has happened to almost all of a society. As a result intangible goods are also included as a major concern in international trade. We may say U.S. is one of the countries transaction of software is the most flourishing. I have tried to classified the cases of software transaction in U.S. into five groups. As a result I have known the UCC had been applied to the almost transaction of standard software. However UCC had not been applied to custom software and data processing. In these days UCITA which is very similar to a previous proposal UCC 2B has been presented. This is a contract law that would apply to computer software, multimedia products, and databases. It has been designed to create a uniform commercial contract law for those products. Now therefore we should make observation of a tendency about transaction of software in U.S. The reason is that we pay attention to the symbol and dormant power of U.S. in international trade.

• 한국언어정보학회지:언어와정보
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• 제8권1호
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• pp.137-161
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• 2004

In this paper, I will look at two conditional connectives in Korean and point out differences between -(u)myen and -ta/la-myen in their distributions and semantics. One of the differences is that -ta/la-myen always allows epistemic interpretation, whereas -(u)myen allows epistemic interpretation only when the event time of the antecedent clause is in the past or present. A second difference is that only -(u)myen is used in purely temporal and habitual conditionals. A third difference is that the modality marker -keyss, which can have volitional or predictive interpretation with -(u)myen, cannot have predictive interpretation with -ta/la-myen. I propose that -ta/la-myen has the operator of settledness, which is defined with respect to the speech time, and explain the differences listed based on the semantics of settledness.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.797-802
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• 2005

We generate simplex polynomials by using a method, which produces an OPS in (d + 1) variables from an OPS in d variables and the Jacobi polynomials. Also we obtain a partial differential equation of the form $${\Sigma}_{i,j=1}^{d+1}\;A_ij{\frac{{\partial}^2u}{{\partial}x_i{\partial}x_j}}+{\Sigma}_{i=1}^{d+1}\;B_iu\;=\;{\lambda}u$$, which has simplex polynomials as solutions, where ${\lambda}$ is the eigenvalue parameter.

• 대한수학회보
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• 제42권1호
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• pp.45-51
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• 2005

In this paper, we establish necessary and sufficient conditions for an exchange ideal to be a qb-ideal. It is shown that an exchange ideal I of a ring R is a qb-ideal if and only if when-ever $a{\simeq}b$ via I, there exists u ${\in} I_q^{-1}$ such that a = $ubu_q^{-1}$ and b = $u_q^{-1}$. This gives a generalization of the corresponding result of exchange QB-rings.

• 대한수학회보
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• 제43권4호
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• pp.711-713
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• 2006

Let R be a semiprime ring and f be an endomorphism on R. If f is a strong commutativity preserving (simply, scp) map on a non-zero ideal U of R, then f is commuting on U.

• 재무관리연구
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• 제26권4호
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• pp.141-163
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• 2009

Using the extensive datasets, I analyze the effect of tick size changes on the intraday patterns of spread and depth. I show that intraday variations in spread (depth) are greater (smaller) with smaller tick size during the early hour of trading and become smaller (larger) during the last hour of trading. And the standardized spreads (depths) are quoted at the lower (higher) levels as the tick size becomes smaller. I also find that U-shaped intraday spread pattern changes to the reverse flat S-shape while inverted U-shaped depth pattern does to the flat S-shape.