• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.548-551
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• 2000

Spinel phase LiF $e_{y}$M $n_{2-y}$ $O_4$samples are synthesized by calcining a LiOH.$H_2O$, Mn $O_2$and F $e_2$ $O_3$mixture at 80$0^{\circ}C$ for 36h in air. Preparing LiF $e_{y}$M $n_{2-y}$ $O_4$showed spinel phase with cubic phase. The ununiform distortion of the crystallite of the spinel LiF $e_{y}$M $n_{2-y}$ $O_4$was more stable than that of the pure. The discharge capacity of the cathode for the Li/LiF $e_{0.1}$M $n_{1.9}$ $O_4$cell at the first than that of the pure. The discharge capacity of the cathode for the Li/LiF $e_{0.1}$M $n_{1.9}$ $O_4$cell at the first cycle and at the 70th cycle was about 113 and 90mAh/g, respectively. This cell capacity was retained about 82% of the first cycle after 70th cycle. Impedance profile of this cell was more stable than that pure. The resistance, the capacitance and chemical diffusion coefficients of lithium ion showed approximately 80$\Omega$, 36133.87$\mu$F ; 1.4$\times$10$^{-8}$ c $m^2$ $s^{-1}$ , respectively. , respectively.ely.

• The Pure and Applied Mathematics
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• v.18 no.4
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• pp.313-328
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• 2011

We investigate the stability of the functional equation f(x+y+z+w)+2f(x)+2f(y)+2f(z)+2f(w)-f(x+y)-f(x+z)-f(x+w)-f(y+z)-f(y+w)-f(z+w)=0 by using a flxed point theorem in the sense of L. C$\breve{a}$adariu and V. Radu.

• Journal of the Korean Mathematical Society
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• v.34 no.1
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• pp.13-21
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• 1997

In recent years M. Hochster and C. Huneke introduced the notions of tight closure of an ideal and of the weak F-regularity of a ring of positive prime characteristic. Here 'F' stands for Frobenius. This notion enabled us to play an important role in a commutative ring theory, and other related topics.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.1-5
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• 2007

The 1R(Infra-Red) spectrum and PL(Photoluminescence) of the antiferromagnetic pure $MnF_2$ and the single crystal $MnF_2(1.5%\;EuF_3)$ with the rutile structures were measured. The detailed analysis of the measured PL data showed the differences of the optical property between the single crystal $MnF_2(1.5%\;EuF_3)$ and the pure $MnF_2$. It was found that the additional PL peak by the doping of the $EuF_3$ in $MnF_2$ is originated from the f-d transition of $Eu^{3+}$ from the temperature dependent intensity measurement.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1597-1609
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• 2015

This paper introduces the fundamentals of the conventional LC low-pass filter circuit in the fractional domain. First, we study the new fundamentals of fractional-order LC low-pass filter circuit including the pure real angular frequency, the pure imaginary angular frequency and the short circuit angular frequency. Moreover, sensitivity analysis of the impedance characteristics and phase characteristics of the LC low-pass filter circuit with respect to the system variables is studied in detail, which shows the greater flexibility of the fractional-order filter circuit in designs. Furthermore, from the filtering property perspective, we systematically investigate the effects of the system variables (LC, frequency f and fractional orders) on the amplitude-frequency characteristics and phase-frequency characteristics. In addition, the detailed analyses of the cut-off frequency and filter factor are presented. Numerical experimental results are presented to verify the theoretical results introduced in this paper.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.424-435
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• 1991

To develop the photoelastic experiment method for the orthotropic material under pure torsional moment is the main objective of this research. In the development of photoelastic experiment for orthotropic material under pure torsional moment, the important problems and their solutions are the same as following. In the model material for photoelastic experiment, it was found that C.F.E.C.(Copper Fiber Epoxy Composite) can be used as the model material of photoelastic experiment for orthotropic material. In the stress freezing cycle, it was assured that stress freezing cycle for epoxy can be used as the stress freezing cycle of the photoelastic experiment for orthotropic material. In the slicing method, it was found that the negative oblique slicing method can be effectively used as slicing method in 3-dimensional photoelastic experiment. In the measuring method of stress fringe values and physical properties in the high temperature, it was found that stress fringe values can be directly measured by experiment and physical properties can be directly or indirectly by equation between stress fringe values and physical properties developed by author. In the stress analysis method of orthotropic material under pure torsional moment by photoelastic experiment, it will be studied in the second paper.

• The Pure and Applied Mathematics
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• v.26 no.4
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• pp.267-276
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• 2019

In this paper, we investigate the stability of an additive-cubic-quartic functional equation f(x + 2y) - 4f(x + y) + 6f(x) - 4f(x - y) + f(x - 2y) - 12f(y) - 12f(-y) = 0 by applying the fixed point theory in the sense of L. Cădariu and V. Radu.

• The Pure and Applied Mathematics
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• v.26 no.4
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• pp.247-254
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• 2019

In this paper, we investigate Hyers-Ulam-Rassias stability of the functional equation f(x + ky) - k²f(x + y) + 2(k² - 1)f(x) - k²f(x - y) + f(x - ky) - k²(k² - 1)(f(y) + f(-y)) = 0, where k is a fixed real number with |k| ≠ 0, 1.

• The Pure and Applied Mathematics
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• v.19 no.1
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• pp.59-71
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• 2012

In this paper, we prove the stability in random normed spaces via fixed point method for the functional equation $$f(x+y+z)-f(x+y)-f(y+z)-f(x+z)+f(x)+f(y)+f(z)=0$$. by using a fixed point theorem in the sense of L. C$\breve{a}$dariu and V. Radu.

• The Pure and Applied Mathematics
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• v.2 no.1
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• pp.31-34
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• 1995

Let R$^n$be n-th Euclidean space. Let be the n-th spere embeded as a subspace in R$\^$n+1/ centered at the origin. In this paper, we are going to consider the function space F = {f│f : S$^n$\longrightarrow S$^n$} metrized by as follow D(f,g)=d(f($\chi$), g($\chi$)) where f, g $\in$ F and d is the metric in S$^n$. Finally we want to find certain relation these spaces.(omitted)