• Advances in aircraft and spacecraft science
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• 제1권2호
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• pp.177-196
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• 2014

A theoretical exploration for determining the characteristic length of the cohesive zone for a double cantilever beam (DCB) specimen under mode I loading was conducted. Two traction-separation laws were studied: (i) a law with only a linear elastic stage from zero to full traction strength; and (ii) a bilinear traction law illustrating a progressive softening stage. Two analytical solutions were derived for the first law, which fit well into two existing solution groups. A transcendental equation was derived for the bilinear traction law, and a graphical method was presented to identify the resultant cohesive zone length. The study using the bilinear traction law enabled the theoretical investigation of the individual effects of cohesive law parameters (i.e., strength, stiffness, and fracture energy) on the cohesive zone length. Correlations between the theoretical and finite element (FE) results were assessed. Effects of traction law parameters on the cohesive zone length were discussed.

• 대한토목학회논문집
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• 제3권3호
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• pp.53-61
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• 1983

침투능을 계산하기 위한 공식으로서 Green-Ampt 공식은 식의 간편성과 정확성으로 인하여 많은 연구의 대상이 되어왔다. 그러나 이 공식의 변수인 습윤전선(Wetting Front)에서의 모세관 압력수두항은 연구자에 따라 해석이 많이 다르다. 침투능해석을 위하여 2개 유체의 흐름방정식의 해는 Green-Ampt 공식과 같은 형태를 가지므로서 Green-Ampt 공식의 모세관 압력 수두항을 결정할 수 있게 되었다. 이러한 2개 유체 해석에 의한 침투능 산정공식의 유도는 1개층으로만 구성되어 있는 경우에 이루어 졌으나 특성이 각각 다른 여러 층의 흙으로 구성 되어 있는 경우에는 아직 이루어진 바 없다. 본 논문에서는 이러한 2개 유체의 흐름 해석에 의하여 여러층의 흙인 경우 침투능 산정공식을 유도하였다.

• 가정과삶의질연구
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• 제20권1호
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• pp.45-56
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• 2002

The main purposes of this article are to introduce the theoretical backgrounds and empirical application methods of two different Models for the function of expenditure, and to compare the goodness-o(-fit of the two models: a single-equation model and a complete-system-of-demand-equation model. For the empirical analysis of the single-equation model, a linear formula and a double-leg formula were employed. In order to test the complete-system-of-demand-equation model empirically, the \"Linear Approximation/Almost Ideal Demand System (LA/AIDS)" was used. The independent variables were the total living expense and expenditure categories Price index. The data used in this study were obtained from the quarterly statistics of "The Annual Report on the Urban Family Income and Expenditure Survey (Dosigagyeyonbo)" and "The Annual Report on the Consumer Price Index (Sobijamulgajaryo)," for the years 1994 to 1997. The goodness-of-fit (R-square) was higher with the complete-system-of-demand-equation model than with the single-equation model for the budget share on food (excluding eating-out expenses) and for the share on cultural and recreational activities. However, there was no difference between the two models in terms of the proportion of the expenditure on automobile fuel.fuel.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.359-364
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• 1998

The effects of boundary conditions on natural frequencies for the ring stiffened composite cylindrical shells are investigated by theoretical method. The Love's thin shell theory and the discrete stiffener theory with beam functions in the Ritz procedure are used to derive the frequency equation. Five different boundary conditions such as clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study. Also, the experimental investigation is presented to validate the theoretical results.

• 전자공학회논문지A
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• 제31A권2호
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• pp.39-44
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• 1994

A theoretical method has been considered for the analysis of a cylindrical edge-slot antenna which belongs to a class of circumferential slot antennas that are suitable for conformal mounting on conducting bodies of revolution. A coupled integral equation is formulated for unknown magnetic currents of both the coaxial aperture and the edge slot, and solved by the moment method. Theoretical values for reflection coefficient obtained based upon the method are compared with our experimental values and other author's results available. There arre good agreement between them.

• 대한화학회지
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• 제7권3호
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• pp.211-215
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• 1963

Inter-relationship between the Hammett equation and the linear enthalpy-entropy effect has been discussed by deriving a new set of equations; ${\Delta}{\Delata}H^{\neq}=a{\sigma}+b{\Delta}{\Delta}S^{\neq}$ and ${\Delta}{\Delta}F^{\neq}=a{sigma}+(b-T){\Delta}{\Delta}S^{\neq}$ where a = -1.36p. Theoretical analysis show that the Hammett, Leffler and Brown equations are special limited forms of these general equations. A necessary and sufficient test of substituent effect can thus be provided by the plot of $({\Delta}{\Delta}H^{\neq}-a{\sigma)$ versus ${\Delta}{\Delta}S^{\neq}$.

• East Asian mathematical journal
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• 제37권3호
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• pp.295-305
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• 2021

In this paper, we analyze the efficiency of a domain decomposition method for the two-dimensional telegraph equations. We formulate the theoretical spectral radius of the iteration matrix generated by the domain decomposition method, because the rate of convergence of an iterative algorithm depends on the spectral radius of the iteration matrix. The theoretical spectral radius is confirmed by the experimental one using MATLAB. Speedup and operation ratio of the domain decomposition method are also compared as the two measurements of the efficiency of the method. Numerical results support the high efficiency of the domain decomposition method.

• East Asian mathematical journal
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• 제33권5호
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• pp.511-525
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• 2017

We introduce an extrapolated higher order characteristic finite element method to construct approximate solutions of a Sobolev equation with a convection term. The higher order of convergence in both the temporal direction and the spatial direction in $L^2$ normed space is established and some computational results to support our theoretical results are presented.

• 천문학논총
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• 제15권1호
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• pp.1-13
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• 2000

Since Goldreich and Julian's pioneering work in 1969, the pulsar magnetosphere theory has been dramatically developed for theorists to possess an elegant axisymmetric, stationary model. Based on this development the black hole magnetosphere theory has also been established in the last 30 years. Such theoretical developments will be reviewd equation by equation in this paper.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.204-209
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• 1997

This paper reports on the theoretical study of the vane motions in a positive displacement vane pump. Vane detachment cause the pressure fluctuation, noise, wear in cam ring, and decrease the volumetric efficiency. Dynamic equation of vane motion and flow continuity equation have been modeled and solved simultaneously using 4th order Runge-Kutta method. As results of analysis, vane detachment occurs due to pressure overshoot by excess compression in the pumping chamber. Amount of vane detachment has been reduced by decreasing the pressure overshoot.