• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1897-1907
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• 1991

An analysis is presented for the primary resonance of a clamped-hinged beam, which occurs when the frequency of excitation is near one of the natural frequencies, .omega.$_{n}$. Three mode interactions, .omega.$_{2}$=3.omega.$_{1}$, and .omega.$_{3}$=.omega.$_{1}$+2.omega.$_{2}$, are considered and their influence on the response is studied. The case of two mode interaction, .omega.$_{2}$=3.omega.$_{1}$, is also considered in order to compare it with the case of three mode interactions. The straight beam experiencing mid-plane stretching is governed by a nonlinear partial differential equation. By using Galerkin's method the governing equation is reduced to a system of nonautonomous nonlinear ordinary differential equations. The method of multiple scales is applied to obtain steady-state responses of the system. Results of numerical investions show that there exists no significant difference between both modal interactions.

• Journal of the Korean Applied Science and Technology
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• v.2 no.1
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• pp.33-36
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• 1985

The fatty acid composition of Phospholipids from human mature milk, modified milk formula and market milk were analyzed by gas-liquid chromatography. The levels of 8:0, 10:0, 19:0, 20:0 and 22:0 were significantly higher in modified milk formula than in human milk. The levels of 14:0 and 16:0 were significantly lower in modified milk formula than in human milk. Modified milk formula had a higher $18:2{\omega}6$ content than human milk (17.9 versus 7.9%). The metabolites of the ${\omega}$9-, ${\omega}$6-$ and ${\omega}$3-series showed lower levels in modified milk formula than in human milk. The fatty acid composition of phospholipids from modified milk formula was similar to that of market milk.

• Korean Journal of Optics and Photonics
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• v.7 no.1
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• pp.77-86
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• 1996

We employ the SOR method to analyze CPW electrodes of Ti:$LiNbO_3$ Mach-Zehnder traveling-wave optical modulator in the tapered region of an optical modulator. In the tapered region of the modulator, we design the electrodes satisfying $Z_c=50{\Omega}$. In the modulation region, we find two find sets of design parameters. One set is for $Z_c=50{\Omega}$, $n_{eff}=2.26$ and the another is for $n_{eff}=2.2$, $Z_c=47.7{\Omega}$.

• Communications of the Korean Mathematical Society
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• v.28 no.3
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• pp.589-596
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• 2013

This paper is an attempt to study and introduce the notion of ${\omega}$-dense set in weak structures and the notion of m-dense set in minimal structures. We have also investigate the relationships between ${\omega}$-dense sets, $m$-dense sets, ${\sigma}({\omega})$ sets, ${\pi}({\omega})$ sets, $r({\omega})$ sets, ${\beta}({\omega})$ sets, m-semiopen sets and $m$-preopen sets. Further we give some representations of the above generalized sets in minimal structures as well as in weak structures.

• Journal of the Chungcheong Mathematical Society
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• v.19 no.3
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• pp.283-289
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• 2006

Roh[1] derived 2D g-Navier-Stokes equations from 3D Navier-Stokes equations. In this paper, we will see the space $L^2({\Omega},\;g)$, which is the weighted space of $L^2({\Omega})$, as natural generalized space of $L^2({\Omega})$ which is mathematical setting for Navier-Stokes equations. Our future purpose is to use the space $L^2({\Omega},\;g)$ as mathematical setting for the g-Navier-Stokes equations. In addition, we will see Helmoltz-Leray projection on $L^2_{per}({\Omega},\;g)$) and compare with the one on $L^2_{per}({\Omega})$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.394-400
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• 2012

In this paper, charging modes of series resonant converter for a high voltage energy storage capacitor are compared in terms of charging time, peak resonant current, normalized peak resonant current and voltage in each operation mode. Operating principles of the full bridge series resonant converter with capacitor load are explained and analyzed in discontinuous and continuous operation mode. Based on the analysis and simulation result, $0.6{\omega}_r$ < ${\omega}_s$ < $0.75{\omega}_r$ and $1.3{\omega}_r$ < ${\omega}_s$ < $1.4{\omega}_r$ are evaluated to the best range of switching frequency for charging of an high voltage energy storage capacitor. 1.8 kJ/s SRC prototype is assembled with TI 28335 DSP controller and 40 kJ, 7 kV energy storage capacitor. Design rules based on the comparative analysis are verified by experiment.

• Journal of Nutrition and Health
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• v.28 no.10
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• pp.995-1003
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• 1995

This study was conducted to asses the $\omega$-3 fatty acid intake levels and to evaluate the relationship between the levels of $\omega$-3 fatty acids in plasma and erythrocyte membrane and the dietary intake of these fatty acids over the period of two months in 56 young Korean females. Dietary survey was conducted to obtain 7-day weiged records and six 24-hour recalls. Fasting blood sample was collected from each subject after the dietary survey period. Mean daily intakes of energy, fat, and cholesterol were 1,569㎉, 41.8g, and 217mg, respectively. Fat suppled 24% of total energy intake. Mean daily intake levels of eicosapentaenoic acid(EPA), docosahexaenoic acid(DHA), and total $\omega$-3 fatty acids were 0.04g, 0.06g, and 0.48g, respectively. Plasma cholesterol levels of most of the subjects were within normal range, and there was no significant correlation between plasma cholesterol levels and intake levels of any specific fatty acid. Levels of EPA, DHA, EPA+DHA in plasma and erythrocyte membrane, but not the levels of $\alpha$-linolenic acid(LNA), were significantly correlated with dietary in take of respective fatty acids. Such a correlation, however, was not observed in a previous study where dietary intake was assessed for 3 days. The results of this study show that dietary intakes of $\omega$-3 fatty acids are low in the subject and that about two-month period is required to assess dietary intake levels of $\omega$-3 fatty acids with a reasonable accuracy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.109-114
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• 1989

To compare antioxidant action of u 3 polyunsaturated fatty acid (PUFA) on lipid peroxidation in rats, the formation of malondialdehyde (MDA) and membranes of liver and brain and activities of antioxidant-related enzymes such as catalase, glutathione peroxidase, and superoxide dismutase (SOD) in blood, were studied. Malondialdehyde contents of $\omega3$ PUFA and sardine oil groups were significantly decreased compared with lard group as control (p<0.05). Catalase and superoxide dismutase showed higher activities in $\omega3$ PUFA and sardine oil groups than those of lard control group. These findings suggest that fish oil has a inhibitory effect on formation of lipid peroxides in blood and membranes of rats.

• The Pure and Applied Mathematics
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• v.3 no.1
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• pp.19-32
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• 1996

A symplectic manifold is a pair (M, $\omega$) consisting of a smooth manifold M and a non-degenerate closed 2-form $\omega$ on M. Locally, $\omega$ = (equation omitted) and d$\omega$ = 0, when n = dimM. The condition d$\omega$ = 0 implies that locally $\omega$ = d${\alpha}$ with ${\alpha}$ = (equation omitted). There are three main sources of symplectic manifolds.(omitted)

• Communications of the Korean Mathematical Society
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• v.9 no.2
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• pp.467-489
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• 1994

Let $\Omega$ be a closed and bounded polygonal domain in R$^2$, or a closed line segment in R$^1$ with boundary $\Gamma$, such that there exists an invertible mapping T : $\Omega$ \longrightarrow $\Omega$ with the following correspondence: x$\in$$\Omega$ ↔ x = T(x) $\in$$\Omega$, (1.1) and (1.2) t $\in$ U$\sub$p/($\Omega$) ↔ t = to T$\^$-1/ $\in$ U$\sub$p/($\Omega$), where $\Omega$ denotes the corresponding reference elements I = [-1,1] and I ${\times}$ I in R$^1$ and R$^2$ respectively, (1.3) U$\sub$p/($\Omega$) = {t : t is a polynomial of degree $\leq$ p in each variable on $\Omega$}, and (1.4) U$\sub$p/($\Omega$) = {t : t = to T $\in$ U$\sub$p/($\Omega$)}.(omitted)