• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.246-249
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• 1995

This paper proposed a partial resonant swtiching three-phase high power factor converter using a lossless snubber. The proposed converter has a merit of simple controlled circuit because tile input current control discontinuously. And it is improve to input power factor that the snubber capacitor's energy regenerate to the AC source side. This topology is reduced a current/voltage stresses of resonant devices in addition to a partial resonant strategy. The result of simulations with the proposed topology included in this paper.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.86-91
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• 2009

The main purpose of this study is to search the water factor which influences to occurrence of the total coliforms. Occurrences rate of the total coliforms and the E coli were 57.9% 10.5% in 2007 and 47.4%, 23.7% in 2008 respectively. According to the result which examines the correlation analysis and a regression analysis, most the water factor which is effect was $Na^+$(0.497, p<0.05) in appearance of the total coliforms and was $Cl^-$(0.622, p<0.01) in appearance of the E coli. The water factor that simultaneously influences to the total coliforms and the E. coli appearances was the $Cl^-$. The predictable regression formula for appearance rate of the total coliforms was expressed as 0.462 + 0.028 [$Na^+$] - 0.644 [$COD_{Mn}$] - 8.889 [$PO_4-P$](R = 0.930, $R^2$ = 0.866, adjusted $R^2$ = 0.839, p<0.05), and that of the E coli was described as -0.012 + 0.004 [$Cl^-$](R = 0.622, $R^2$ = 0.387, adjusted $R^2$ = 0.351, p<0.05).

• Journal of the Korean Society for Railway
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• v.10 no.3 s.40
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• pp.264-270
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• 2007

Two modulus, strain modulus $(E_v)$ and subgrade reaction modulus $(K_{30})$ are being used as a standard for bearing stiffness in Korea Railroad design. The first is used in Europe and the other is used in Japan. The methodologies to obtain the two modulus are similar in using plate. But testing methods are different in loading to plate. Therefore, according to soil strain range, there should be large gap in not only computations of deformation modulus but also the necessary time to test. At first, this paper focuses on the two kinds of test methods to evaluate bearing stiffness. Secondly, based on elastic theory, the theory to obtain the two coefficients are studied thoroughly. Finally, the correlations between the two coefficients were analyzed and evaluated based on the field test results more than 38 places. The matching values for subgrade and ground between $K_{30}$ and $E_{v2}$ are proposed with the consideration of the proposed strain reduction factor (1.5 for subgrade and 3 for ground) and safety factor, respectively.

• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.193-198
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• 2016

Early-type galaxies (ETGs) are supposed to follow the virial relation $M=k_e{\sigma}^2R_e/G$, with M being the mass, σ_* being the stellar velocity dispersion, R_e being the effective radius, G being Newton's constant, and k_e being the virial factor, a geometry factor of order unity. Applying this relation to (a) the ATLAS^3D sample of Cappellari et al. (2013) and (b) the sample of Saglia et al. (2016) gives ensemble-averaged factors 〈k_e〉 = 5.15 ± 0.09 and 〈k_e〉 = 4.01 ± 0.18, respectively, with the difference arising from different definitions of effective velocity dispersions. The two datasets reveal a statistically significant tilt of the empirical relation relative to the theoretical virial relation such that $M{\propto}({\sigma}^2_*R_e)^{0.92}$. This tilt disappears when replacing R_e with the semi-major axis of the projected half-light ellipse, a. All best-fit scaling relations show zero intrinsic scatter, implying that the mass plane of ETGs is fully determined by the virial relation. Whenever a comparison is possible, my results are consistent with, and confirm, the results by Cappellari et al. (2013). The difference between the relations using either a or R_e arises from a known lack of highly elliptical high-mass galaxies; this leads to a scaling (1 - ϵ ) ∝ M^0.12, with ϵ being the ellipticity and $R_e=a\sqrt[]{1-{\epsilon}}$. Accordingly, a, not R_e, is the correct proxy for the scale radius of ETGs. By geometry, this implies that early-type galaxies are axisymmetric and oblate in general, in agreement with published results from modeling based on kinematics and light distributions.

• Korean Journal of Plant Tissue Culture
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• v.28 no.5
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• pp.283-287
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• 2001

Differential display based on PCR was employed to identify genes expressed during tuber-developing stage of potato (Solanum tuberosum L. cv. Irish Cobbler). An eukaryotic initiation factor 5A (eIF-5A) clone isolated from a cDNA library constructed with developing micro-tuber using a probe of PCR fragment. We isolated three positive clones and ore of them contained open reading frame. This clone revealed high sequence similarity to tomato eIF 5A cDNA. At the DNA level, there is 94.8% identity with the tomato eIF-5A4, whereas at the protein level there is a high identity with 97.5%. The potato eIF 5A clone is 716 bp in length and contains a single open reading frame from 57 to 539 bp, a 56 bp 5'-untranslated region and a 177 bp 3'-untranslated region. The deduced protein composed of 160 amino acid residues, with a predicted molecular mass of 17.4 kD and an estimated pl of 5.5. The sequence of 12 (STSKTGKHGHAK) amino acids among eIF-5A proteins is perfectly conserved from yeast to human. That sequence in potato eIF-5A protein is also conserved at position 46 to 57 amino acid. This region embeds the post-translational modification site of the lysine residue (at the seventh K) to hypusine that is crucial to eIF-5A activity. The northern blot analysis of eIF5A has shown abundant expression, mainly in flower organs (stamen, ovary, petal, sepal), fruit and stolen.

• Biomedical Science Letters
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• v.15 no.3
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• pp.179-185
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• 2009

In our previous report, we showed that $PPAR{\gamma}$ does not influence adipogenesis in females with functioning ovaries, indicating that $PPAR{\gamma}$ activity on adipogenesis is associated with sex-related factors. Among the sex-related factors, estrogen has been recognized as a major factor in inhibiting adiposgenesis in females. Thus, we hypothensized that $17{\beta}$-estradiol (E) inhibits 3T3-L1 cell adipogenesis by preventing $PPAR{\gamma}$ activity. E decreased triglyceirde accumulation in differentiated 3T3-L1 cells compared with control group. E also decreased the expression of $PPAR{\gamma}$ mRNA as well as $PPAR{\gamma}$ dependent adipocyte-specific genes, such as adipocyte fatty acid binding protein and tumor necrosis factor $\alpha$. In addition, E not only decreased luciferase reporter activity by $PPAR{\gamma}$, but also transfection of estrogen receptor $\alpha$ ($ER{\alpha}$) or $ER{\beta}$ led to decreases in $PPAR{\gamma}$ reporter gene activation. Moreover, E-activated ERs significantly decreased the luciferase reporter gene activation induced by $PPAR{\gamma}$ transfection, suggesting that estrogen-activated ERs inhibit $PPAR{\gamma}$-dependent transactivation. Accordingly, our results demonstrate that E inhibits the action of $PPAR{\gamma}$ on adipogenesis through E activated ER, providing evidence that lack of estrogen may potentiate $PPAR{\gamma}$ action on adipogenesis.

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.05a
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• pp.350-351
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• 2004

• Journal of Digital Convergence
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• v.18 no.1
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• pp.369-377
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• 2020

The purpose of this study is to find out the effect of e-learning quality and learner's usage motivation on e-learning satisfaction in Korea and China. In addition, by comparing and analyzing the factors influencing the satisfaction of learners between the two countries, this study aims to suggest the effective use of e-learning. This study surveyed Korean university students at Y and K universities in Gyeongsangbuk-do and Chinese university students at A university in Henan, China. As a result, for Korean university students, it is showed that learning time, learning space, learning process, usefulness, e-learning information quality, and service quality affect e-learning satisfaction. For Chinese university students, learning time, learning process and e-learning system quality, information quality, and service quality were found to affect e-learning satisfaction. Among them, service quality was an important factor influencing e-learning satisfaction in both countries, but the average score of each factor was very low. In the future, we discussed ways to improve service quality.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.51-58
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• 1985

A simple model for the impurity profile in an ion-implanted channel layer of an enhance-ment type IGFET is assumed and a simple expression for the threshold voltage is derived by the assumed impurity profile. In application, the concept of correction factor K is used and the value of threshold voltage is well agreed with experimental value. Also, 1-V character-istics curve is well agreed with experimental value. In addition, this program is packaged and is utilized.

• Preventive Nutrition and Food Science
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• v.11 no.1
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• pp.1-5
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• 2006

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of linoleic acid that have been used to reduce the incidence, growth and metastasis of breast, colon, prostate and gastric cancer in animals. CLA could reduce tumor growth by altering angiogenesis; a process requiring associated angiogenic factors such as vascular endothelial growth factor (VEGF). In this study, we determined whether CLA could modulate the expression of VEGF in murine mammary tumor cells and adipocytes. The c9, t11-CLA isomer reduced VEGF transcripts and protein when mammary tumor cells were stimulated with PMA. That isomer also reduced VEGF expression in un stimulated mouse 3T3-L1 adipocytes. Since VEGF can be regulated by cyclooxygenase-2 (COX-2), we determined whether CLA could alter COX-2 enzyme expression and $PGE_2$ production. The c9, t11-CLA isomer reduced not only COX-2 enzyme expression but also $PGE_2$ production. Thus, c9, t11-CLA could modulate neovascularization by alteration of VEGF expression from mammary tumor cells and adipocytes by reducing COX-2 metabolites.