• 대한기계학회논문집B
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• 제23권5호
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• pp.610-620
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• 1999

Recently, numerous modifications of low Reynolds number $k-{\epsilon}$ model have boon carried out with the aid of DNS data. However, the previous models made in this way are too intricate to be used practically. To overcome this shortcoming, a new low Reynolds number $k-{\epsilon}$ model has boon developed by considering the distribution of turbulent properties near the wall. This study proposes the revised a turbulence model for prediction of turbulent flow with adverse pressure gradient and separation. Nondimensional distance $y^+$ in damping functions is changed to $y^*$ and some terms modeled for one dimensional flow in $\epsilon$ equations are expanded into two or three dimensional form. Predicted results by the revised model show an acceptable agreement with DNS data and experimental results. However, for a turbulent flow with severe adverse pressure gradient, an additive term reflecting an adverse pressure gradient effect will have to be considered.

• 한국통신학회논문지
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• 제33권11C호
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• pp.874-879
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• 2008

[1]에서 LCZ 수열군의 2배 확장을 제안하였다. 본 논문에서는 [1]에서의 2배 확장방법을 일반화하는 새로운 확장방법을 제안한다. 이 생성방법을 사용하면 인수가 (N,M,L,${\epsilon}$)인 q진 LCZ 수열군은 인수가 (pN,pM,p[(L+1)/p]-1,p${\epsilon}$)인 q진 LCZ 수열군이 된다. 이 때, p는 소수이고 p는 q의 약수다. 특히 L${\equiv}$p-1modp일 때, 확장된 q진 LCZ 수열군의 인수는 (pN,pM,L,p${\epsilon}$)이 된다.

• Korean Journal of Mathematics
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• 제22권1호
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• pp.169-180
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• 2014

In this study, we consider the informal and formal definition of limit on the basis of middle and high school curriculum, and then analyze the reason of difficulties experienced when sophomores learn the formal definition(${\epsilon}-{\delta}$ procedure) of limit. We conducted teaching of the formal definition of limit with sophomores and analyzed their errors which were appeared when they applied to limits problems. In addition, we try to improve the understanding of ${\epsilon}-{\delta}$ procedure of the limit taught in analysis.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제9권1호
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• pp.19-30
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• 2002

We consider one class of bursting oscillation models, that is square-wave burster. One of the interesting features of these models is that periodic bursting solution need not to be unique or stable for arbitrarily small values of a singular perturbation parameter $\epsilon$. Recent results show that the bursting solution is uniquely determined and stable for most of the ranges of the small parameter $\epsilon$. In this paper, we present a condition of uniqueness and stability of periodic bursting solutions for all sufficiently small values of $\epsilon$ > 0.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.125-126
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• 2008

A near-ring N is called strongly reduced if, for a ${\epsilon}$ N, $a^2\;{\epsilon}\;N_c$ implies a ${\epsilon}\;N_c$, where $N_c$ denotes the constant part of N. We investigate some properties of strongly reduced near-rings and apply those to the study of left strongly regular near-rings. Finally we classify some reduced, and strongly reduced near-rings.

• 약학회지
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• 제27권2호
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• pp.177-179
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• 1983

A copper complex of $\epsilon$-N-[(2-chloroethyl)carbamoyl]-L-lysine was prepared by the treatment of the L-lysine copper complex with 2-chloroethyl isocyanate in cold water. Within the L-lysine copper complex molecule, the $\alpha-amino$ and carboxyl groups are bounded to $Cu^{2+}$ but the $\epsilon-amino$ group is free and can react with carbamoylating agents. A potential antitumor agent, $\epsilon-N-[(2-chloroethyl)$ nitrosocarbamoyl]-L-lysine was synthesized by nitrosation of this copper complex with Na $NO_{2}$ in anhydrous formic acid, followed by the passage of $H_{2}$S gas.

• EDISON SW 활용 경진대회 논문집
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• 제2회(2013년)
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• pp.193-202
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• 2013

본 연구는 두개의 서로 다른 LJ 입자가 혼합된 계에 대하여 이들 사이의 LJ parameter 변화가 어떠한 영향을 미치는지 모의실험을 하였다. 조사 대상은 비활성 기체인 He과 Xe을 기준으로 하여 이들의 LJ parameter를 기준값으로부터 일정하게 변화시키며 열용량을 관찰하여 진행하였다. 분자간 상호작용만을 고려하여, 단원자 기체인 비활성 기체의 Lennard-Jones potential energy를 구하였다. Epsilon 값과 sigma 값을 바꿔 Lennard-Jones potential energy의 변화를 알아보고자 한다. 본 연구를 통해 sigma, epsilon 값이 클수록 Lennard-Jones potential energy가 커진다는 것을 알 수 있었다.

• 대한수학회논문집
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• 제27권2호
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• pp.297-306
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• 2012

In this paper we study (${\epsilon}$)-Lorentzian para-Sasakian manifolds and show its existence by an example. Some basic results regarding such manifolds have been deduced. Finally, we study conformally flat and Weyl-semisymmetric (${\epsilon}$)-Lorentzian para-Sasakian manifolds.

• 충청수학회지
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• 제21권3호
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• pp.339-345
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• 2008

We prove the existence of the positive solution for the nonlinear system of suspension bridge equations with Dirichlet boundary condition and periodic condition $$\{u_{tt}+u_{xxxx}+av^+=1+{\epsilon}_1h_1(x,t)\text{ in }(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,\\v_{tt}+v_{xxxx}+bu^+=1+{\epsilon}_2h_2(x,t)\text{ in }(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,$$ where $u^+={\max}\{u,0\},\;{\epsilon}_1,\;{\epsilon}_2$ are small numbers and $h_1(x,t)$, $h_2(x,t)$ are bounded, ${\pi}$-periodic in t and even in x and t and ${\parallel}h_1{\parallel}={\parallel}h_2{\parallel}=1$.

• 설비공학논문집
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• 제15권12호
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• pp.1095-1102
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• 2003

Flow characteristics of turbulent steady fluid flow past a cylinder in rectangular duct are measured by 5 W laser doppler velocity meter. The fluid flow is also computed by commercial software of STAR-CD for comparison between the measurement and computation. The turbulent models applied in the computations are standard K-epsilon model, RNG K-epsilon model and Chen K-epsilon model. Acurracy of standard K-epsilon model is a little bit better than acurracies of other models even though those models have almost the same order of error compared to measured data. The computations predict satisfactorily the measured velocity profiles at middle section of the circular cylinder before the fluid flow diverges. However, there are some disagreements between them at down stream from the circular cylinder.