• Wind and Structures
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• v.29 no.1
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• pp.43-53
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• 2019

Vortex-induced vibration of three circular cylinders (each of diameter D) in an equilateral triangular arrangement is investigated using the immersed boundary method. The cylinders, with one placed upstream and the other two side-by-side downstream, are free to vibrate in the cross-flow direction. The cylinder center-to-center spacing L is adopted as L/D = 2.0. Other parameters include the Reynolds number Re = 100, mass ratio $m^*=2.0$, reduced velocity $U_r=2{\sim}15$ and damping ratio ${\zeta}=0$. Cylinder vibration responses are dependent on $U_r$ and classified into five regimes, i.e. Regime I ($U_r{\leq}3.2$), Regime II ($3.2<U_r{\leq}5.0$), Regime III ($5.0<U_r{\leq}6.4$), Regime IV ($6.4<U_r{\leq}9.2$) and Regime V ($U_r>9.2$). Different facets of vibration amplitude, hydrodynamic forces, wake patterns and displacement spectra are extracted and presented in detail for each regime.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.3
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• pp.237-241
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• 2015

To develop a new anti-inflammation agent for cosmetics, we investigated the anti-inflammatory activity of Fallopia sachalinensis RonseDecr. fruit extracts (FSR). FSR inhibited the pre-inflammatory cytokines ($1L-1{\beta}$, IL-6, TNF-${\alpha}$) and reduced NO production of RAW 264.7 macrophage cells in a dose-dependent manner and decreased the activity to about 51% at a concentration of $100{\mu}g/mL$. FSR suppressed not only the mRNA expression of iNOS and COX-2, but also the protein expression of iNOS and COX-2 in macrophage. The results suggested that FSR has considerable potential as a cosmetics ingredient with an anti-inflammatory effect.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.444-450
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• 2006

Skin anti-aging effect of Forsythia viridissima L. extract was evaluated by using antioxidant assay, expression of type I procollagen, and UVA-induced matrix metalloproteinase-1 in human dermal fibroblasts. Matairesinol-rich Forsythia viridissima L. extract was showed the scavenging activity of radicals and reactive oxygen species with the $IC_{50}$ values of $4.50\;{\mu}m/ml$ against 1,1-diphenyl-2-picrylhydrazly radical and $542.43\;{mu}m/ml$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. The type I procollagen was increased 33.76% by treatment with matairesinol-rich Forsythia viridissima L. extract, and UVA-induced MMP-1 was reduced 35.78% in a dose dependent manner. In the human skin irritation test, 2% matairesinol-rich Forsythia viridissima L. extract did not show any adverse effect. Also, the clinical study indicated that a cream group treated with 0.2% matairesinol-rich Forsythia viridissima L. extract significantly reduced skin wrinkles, as compared with a non-treated cream group (p < 0.05). These results suggest that Forsythia viridissima L. extract may be useful as a potential source of functional anti-aging cosmetics.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.44-52
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• 2006

New organotin(IV) derivatives with general formulae R_2SnL_2 and R_3SnL, where R = methyl, n-butyl, n-octyl and phenyl and HL is either 3-[N-(4-nitrophenyl)amido]-propenoic acid or 3-[N-(4-nitrophenyl)amido] propanoic acid have been synthesized in 1 : 2 and 1 : 1 molar ratio by different methods. The FTIR spectra clearly demonstrated that the organotin(IV) moieties react with [O,O] atoms of the ligands. The bonding and coordination behavior in these complexes are discussed on the basis of multinuclear (^1H,\,^{13}C,\,^{119}Sn) NMR and mass spectrometric studies. Antibacterial, and antifungal screening tests were performed for these compounds and reported here. These values were compared to those of the precursors and it was found that diorganotin(IV) complexes exhibit less activity as compared to triorganotin(IV) complexes . LD_{50} data were obtained by Brine Shrimp assay method. Insecticidal activity was performed for selective compounds by contact toxicity method.

• Journal of the Chungcheong Mathematical Society
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• v.13 no.2
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• pp.1-7
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• 2001

In this paper, we show that for a homotopically periodic (i.e., $fk{\simeq}id$, for some $k{\geq}1$) self map f of a Seifert 3-manifold with $P{\widetilde{SL(2,}}\mathbb{R})$-geometry, N(f) = L(f) = 0.

• Korean Journal of Materials Research
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• v.11 no.3
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• pp.171-177
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• 2001

The thermal and mechanical properties of amorphous Z $r_{62-x}$N $i_{10}$C $u_{20}$A $l_{8}$ $Ti_{x}$ (x=3, 6, 9at%) alloys were investigated. The crystallization process was confirmed as amorphous longrightarrow amorphous + Z $r_2$A $l_3$+ Zr + (Ni,Ti) longrightarrow Z $r_2$Cu + Al + (Ni,Ti) for 3at%Ti, amorphous longrightarrow amorphous + Al longrightarrow $Al_2$Ti + NiZr + CuTi for 6at%Ti and amorphous longrightarrow amorphous + Zr + Al longrightarrow Zr + $Al_2$Zr + Al $Ti_3$+ CuTi for 9at%Ti. lickers hardness ( $H_{v}$ ) increased with increasing volume fraction( $V_{f}$ ) of pricipitates for all concerned compositions. Tensile fracture strength ($\sigma_{f}$ ) showed a maximum value 1219MPa at $V_{f}$ = 38% for 3at%Ti, 1203MPa at $V_{f}$ = 2% for 6at%Ti and 1350MPa at $V_{f}$ = 5% for 9at%Ti. The $\sigma_{f}$ was rapidly decreased after showing the maximum value. The $V_{f}$ corresponding to rapidly decreased $\sigma_{f}$ coincided with the $V_{f}$ transited from ductile to brittle fracture surface.ace.

• The Journal of Internal Korean Medicine
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• v.26 no.1
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• pp.93-106
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• 2005

Objectives : The aim of this study is to characterize the effect of Chungganhaeju-tang on $TGF-{\beta}l$-induced hepatic fibrosis. Materials and Methods : mRNA and protein expression levels of $TGF-{\beta}l$ in Chungganhaeju-tang treated HepG2 cells were compared to untreated cells using quantitative RT-PCR and ELISA assay, respectively. mRNA expression levels of the $TGF-{\beta}l$ signaling pathway genes $(T{\beta}R-I,\;T{\beta}R-II,\;Smad2,\;Smad3,\;Smad4,\;and\;PAI-1)$ and fibrosis-associated genes (CTGF, fibronectin, and collagen type $l{\alpha}$) were evaluated by quantitative RT-PCR. The effect of Chungganhaeju-tang on cell proliferation of T3891 human fibroblast was evaluated using $[^3H]Thymidine$ Incorporation Assay. Results : Inhibition of $TGF-{\beta}l$ mRNA expression and protein production was observed with treatment of Chungganhaeju-tang and seen to be dose and time dependent. Whereas $TGF-{\beta}l$-mediated induction of PAI-1 was suppressed with treatment of Chungganhaeju-tang, expression of the $TGF-{\beta}l$ signaling pathway genes such as $T{\beta}R-I$, $T{\beta}R-II$, Smad2, Smad3, and Smad4 was not affected. With treatment of Chungganhaeju-tang, inhibition of $TGF-{\beta}l$-induced cell proliferation of T3891 human fibroblast was observed, as well as abrogation of $TGF-{\beta}l$-mediated transcriptional up-regulation of CTGF, fibronectin, and collagen type $I{\alpha}$. Conclusion : This study strongly suggests that the liver cirrhosis-suppressive activity of Chungganhaeju-tang may be derived at least in part from its inhibitory effect on $TGF-{\beta}l$ functions, such as blockade of $TGF-{\beta}l$ stimulation of fibroblast cell proliferation and fibrosis-related gene expression as well as expression of $TGF-{\beta}l$ itself.

• Proceedings of the Korean Aquaculture Society Conference
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• 2001.12a
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• pp.280-281
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• 2001

• Bulletin of the Korean Mathematical Society
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• v.52 no.3
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• pp.977-986
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• 2015

Let G be a graph on the vertex set $V(G)=\{x_1,{\cdots},x_n\}$ with the edge set E(G), and let $R=K[x_1,{\cdots},x_n]$ be the polynomial ring over a field K. Two monomial ideals are associated to G, the edge ideal I(G) generated by all monomials $x_i,x_j$ with $\{x_i,x_j\}{\in}E(G)$, and the vertex cover ideal $I_G$ generated by monomials ${\prod}_{x_i{\in}C}{^{x_i}}$ for all minimal vertex covers C of G. A minimal vertex cover of G is a subset $C{\subset}V(G)$ such that each edge has at least one vertex in C and no proper subset of C has the same property. Indeed, the vertex cover ideal of G is the Alexander dual of the edge ideal of G. In this paper, for an unmixed bipartite graph G we consider the lattice of vertex covers $L_G$ and we explicitly describe the minimal free resolution of the ideal associated to $L_G$ which is exactly the vertex cover ideal of G. Then we compute depth, projective dimension, regularity and extremal Betti numbers of R/I(G) in terms of the associated lattice.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1989-1992
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• 1997

A new soft switching single stage AC-DC full bridge boost converter with unit input power factor and isolated output is presented. Due to using of the non-dissipative snubber in the primary side, a single stage high-power factor isolated full bridge boost converter has a significant reduction of switching losses in main switching devices and output rectifiers of the primary and secondary side, respectively. The non-dissipative snubber adopted in this study is consisted of a snubber capacitor C. and a snubber inductor $L_r$, a fast recovery snubber diode $D_r$, a commutation diode $D_p$. This paper presents the complete operating principles, theoretical analysis and simulation results.