• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1239-1249
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• 2013

In this study we establish a process to predict hardening behavior considering the Bauschinger effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Bauschinger effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with FEA. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments.

• Analytical Science and Technology
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• v.15 no.3
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• pp.243-247
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• 2002

A rapid and simple determination of diazepam in intact diazepam tablets has been investigated using the near infrared spectroscopy(NIRS) combined with partial least squares regession. The separate calibration curves of 2 mg and 5 mg diazepam tablets were studied, as well as the linearity, concentration range and reproducibility of those calibration curves were evaluated. The correlation coefficients of calibration curves of 2 mg and 5 mg diazepam tablets are 0.9416 and 0.9159, respectively and the standard errors of calibration curves(SEC) are 0.018% and 0.032%, respectively.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.1-12
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• 2009

A new mix design procedure for cold in-place recycling using foamed asphalt (CIR-foam) has been developed for Iowa Department of Transportation. Some strengths and weaknesses of the new mix design parameters were considered and modified to improve the laboratory test procedure. Based on the critical mixture parameters identified, a new mix design procedure was developed and validated to establish the properties of the CIR-foam mixtures. As part of the validation effort to evaluate a new CIR-foam mix design procedure, dynamic moduli of CIR-foam mixtures made of seven different reclaimed asphalt pavement (RAP) materials collected throughout the state of Iowa were measured and their master curves were constructed. The main objectives of this study are to provide: 1) standardized testing procedure for measuring the dynamic modulus of CIR-foam mixtures using new simple performance testing (SPT) equipment; 2) analysis procedure for constructing the master curves for a wide range of RAP materials; and 3) impacts of RAP material characteristics on the dynamic modulus. Dynamic moduli were measured at three different temperatures and six different loading frequencies and they were consistent among different RAP sources. Master curves were then constructed for the CIR-foam mixtures using seven different RAP materials. Based upon the observation of the constructed master curves, dynamic moduli of CIR-foam mixtures were less sensitive to the loading frequencies than HMA mixtures. It can be concluded that at the low temperature, the dynamic modulus is affected by the amount of fines in the RAP materials whereas, at the high temperature, the dynamic modulus is influenced by the residual binder characteristics.

• Journal of Astronomy and Space Sciences
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• v.10 no.2
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• pp.113-122
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• 1993

Using a simple analytic model based on the MHD stability arguments we obtain the size of the magnetosphere for the magnetic compact stars. We assume the ordered, field-aligned flow in the magnetosphere and estimate the wellknown Alfven radius. The dependence of the X-ray absorption in the magnetic funnel on the size of this radius is further considered. We show that such a determination of the magnetic interaction radius can be applied to the reconstruction of X-ray light curves of the magnetic binary stars.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.57
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• pp.113-122
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• 2000

A mixture of two distributions, each belonging to the same known Weibull distributions, is proposed and a simple graphical method for estimating the parameters of the Weibull distribution is applied. It appears from the results of this study that the mixed Weibull distribution is an appropriate expression for describing industrial property mortality characteristics.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.130-131
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• 2006

Real elastomers show the anomalous behavior in the Ii dependence curves of the derivatives of W with respect to Ii at small strains. The limiting values of the derivatives were evaluated by a simple model based on the assumption that W in the large deformations should coincide with that in the linear elasticity theory. The calculated values were in good agreement with the experimental ones for real elastomers.

• Honam Mathematical Journal
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• v.29 no.1
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• pp.101-118
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• 2007

The notions of digital k-homotopy equivalence and digital ($k_0,k_1$)-homotopy equivalence were developed in [13, 16]. By the use of the digital k-homotopy equivalence, we can investigate digital k-homotopy equivalent properties of Cartesian products constructed by the minimal simple closed 4- and 8-curves in $\mathbf{Z}^2$.

• YAKHAK HOEJI
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• v.23 no.3_4
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• pp.129-132
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• 1979

The ORD and CD for hyoscine-N-butylbromide present curves of negative Cotton effect in 190-250nm region. The values of .alpha./sub 232/ .alpha./sub 208/, vertical bar .alpha./sub 232/ vertical bar + vertical bar .alpha./sub 208/ and .theta./sub 221.5/ have linearities in the range of lower concentration (hyoscine-N-butylbromide 0.01-0.1w/v%). It is possible to determine the optical purity of hyoseine-N-butylbromide by using these linearities. This experiment is extremely simple and less time-consuming than other methods for estimating optical purity.

• Honam Mathematical Journal
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• v.25 no.1
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• pp.153-162
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• 2003

Recently, the generalized digital $(k_{0},\;k_{1})$-continuity and its properties are investigated. Furthermore, the k-type digital fundamental group for digital image has been studies with the generalized k-adjacencies. The main goal of this paper is to find some properties of the k-type digital fundamental group of Boxer and to investigate some properties of minimal simple closed k-curves with relation to their embedding into some spaces in ${\mathbb{Z}}^n(2{\leq}n{\leq}3)$.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.48-55
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• 1998

We propose a new static current source model and parameter extraction method for AlGaAs/GaAs HBT. The proposed model has 9 parameters describing internal currents and are experessed with the physically meaningful parameters.The proposed parameter extraction method uses the measured dC IV curves and does not need the gummel plt data and any optimization process. the constructed model based on the proposed method predicts the measured data well.