• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.79-86
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• 1998

The nonlinear analytic function expansion nodal (AFEN) method is applied to the solution of the time-dependent neutron diffusion equation. Since the AFEN method requires both the particular solution and the homogeneous solution to the transient fixed source problem, the derivation solution method is focused on finding the particular solution efficiently. To avoid complicated particular solutions, the source distribution is approximated by quadratic polynomials and the transient source is constructed such that the error due to the quadratic approximation is minimized. In addition, this paper presents a new two-node solution scheme that is derived by imposing the constraint of current continuity at the interface corner points. The method is verified through a series of applications to the NEACRP PWR rod ejection benchmark problem.

• Journal of Sericultural and Entomological Science
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• v.45 no.2
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• pp.121-125
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• 2003

Dissolution of Antheraea pernyi silk fiber was carried out in a zinc nitrate 6 hydrate (Zn(NO$_3$)$_2$ㆍ6$H_2O$) solution with various dissolving conditions. The solubility was significantly dependent on the concentration of zinc nitrate, dissolving temperature and time. Regenerated A. pernyi silk fibroin powder was obtained through dialysis process to remove chaotropic salt. FTIR and X-ray diffractometer showed that the conformation of regenerated A. pernyi silk powder was sheet structure.

• Korean Journal of Acupuncture
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• v.17 no.1
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• pp.179-190
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• 2000

This study was undertaken to determine whether Juglandis semen extract solution (JLS solution) exerts protective effect against oxidant-induced inhibition of glutamate uptake by synaptosomes. Synaptosome was prepared from rabbit brain cortex. Glutamate uptake increased by incubation time during 10 minutes, which was significantly inhibited by 1mM t-buthylhydroperoxide(t-BHP). JLS solution prevented t-BHP-induced inhibition of glutamate uptake in a dose-dependent manner. t-BHP reduced glutamate uptake in dose-dependent fashion, which was significantly prevented by 2% JLS solution. t-BHP(1mM) and $ascorbate/Fe^{2+}(50/1{\mu}M)$ increased lipid peroxidation in synaptosomes by 5-fold, and it was significantly prevented by 2% JLS solution. $HgCl_2(0.1mM)$ inhibited glutamate uptake and increased lipid peroxidation. These changes were prevented by 2% JLS solution. Synaptosomal Na-K-ATPase activity was inhibited by t-BHP(1mM) and $H_2O_2(50mM)$, which was prevented by 2% JLS solution. The results indicate that JLS solution prevents oxidant-induced inhibition of glutamate by synaptosomes, and this may result from inhibition of lipid peroxidation induced by oxidants.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.4
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• pp.303-312
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• 1998

To obtain the solution to the time-dependent particle size distribution of an aerosol undergoing gravitational coagulation, the moment method was used which converts the non linear integro-differential equation to a set of ordinary differential equations. A semi-numerical solution was obtained using this method. Subsequently, an analytic solution was given by approximating the collision kernel into a form suitable for the analysis. The results show that during gravitational coagulation, the geometric standard deviation increases and the geometric mean radius decreases as time increases.

• Bulletin of the Korean Mathematical Society
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• v.37 no.2
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• pp.229-247
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• 2000

This paper is concerned with the impulsive Cauchy problem where the control function u is a possibly discontinuous vector-valued function with finite total variation. We assume that the vector fields f, $g_i$(i=1,…, m) are dependent on the time variable. The impulsive Cauchy problem is of the form x(t)=f(t,x) +$\SUMg_i(t,x)u_i(t)$, $t\in$[0,T], x(0)=$\in\; R^n$, where the vector fields f, $g_i$ : $\mathbb{R}\; \times\; \mathbb{R}\; \longrightarrow\; \mathbb(R)^n$ are measurable in t and Lipschitz continuous in x, If $g_i's$ satisfy a condition that $\SUM{\mid}g_i(t_2,x){\mid}{\leq}{\phi}$ $\forallt_1\; <\; t-2,x\; {\epsilon}\;\mathbb{R}^n$ for some increasing function $\phi$, then the imput-output function can be continuously extended to measurable functions of bounded variation.

• Steel and Composite Structures
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• v.46 no.2
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• pp.253-261
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• 2023

The goal of this paper is to investigate dynamic responses of simply-supported laminated micro beams under moving load. In the considered micro-scale problem, the modified coupled stress theory which includes the length scale parameter is used. The governing equations of problem are derived by using the Lagrange procedure. In the solution of the problem the Ritz method is used and algebraic polynomials are used with the trivial functions for the Ritz method. In the solution of the moving load problem, the Newmark average acceleration method is used in the time history. In the numerical examples, the effects of stacking sequence of laminas, fibre orientation angles and the length scale parameter on the dynamic responses of laminated micro beams are examined and discussed.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.4
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• pp.749-756
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• 2013

In this paper, we consider a diffusive delayed predator-prey model with Beddington-DeAngelis type functional response under homogeneous Neumann boundary conditions, where the discrete time delay covers the period from the birth of immature preys to their maturity. We investigate the global existence of nonnegative solutions and the long-term behavior of the time-dependent solution of the model.

• Journal of Information Technology Applications and Management
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• v.20 no.3_spc
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• pp.169-185
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• 2013

In this research, for find out how operations efficiency for ERP systems, after introducing ERP to manufacturing firms with DEA technique. According to research analyzed relative time dependent efficiency, using Time Window Analysis. And for company group and the other firm within the each same Industry, the relative effectiveness of each company group establishment was compared using DEA.

• Korean Management Science Review
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• v.13 no.1
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• pp.13-27
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• 1996

This paper considers the sequencing problem in mixed model assembly lines with hybrid workstation types and sequence-dependent setup times. Computation time is often a critical factor in choosing a method of determining the sequence. We develop a mathematical formulation of the problem to minimize the overall length of a line, and present a tabu search technique which can provide a near optimal solution in real time. The proposed technique is compared with a genetic algorithm and a branch-and-bound method. Experimental results are reported to demonstrate the efficiency of the technique.

• Nuclear Engineering and Technology
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• v.2 no.4
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• pp.263-268
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• 1970

The spectrum of continuous transfer operator arising in a time-energy dependent neutron transport equation is analyzed. Four theorems concerning on the spectrum are proved. A convolution theorem of the generalized Mellin energy transform is given. Also the completeness theorem necessary for a final solution is proved. A unique time decay constant 1 - c is found, which is dominant asymptotically.