• Title/Summary/Keyword: Molecular structures

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Anti-inflammatory Action of Calorie Restriction for Life-Prolongation: A Possible Mechanism

  • Chung, Hae-Young
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.173-174
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    • 2002
  • Oxidative modification of cellular structures and functions by redox imbalance is the basis of the current oxidative stress hypothesis of aging. The experimental support for this hypothsis has been generated from recent molecular probing on the interrelation between the age-related functional impairments and the pathogenesis. (omitted)

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EXISTENCE OF PERIODIC SOLUTIONS IN FERROELECTRIC LIQUID CRYSTALS

  • Park, Jinhae
    • Journal of the Chungcheong Mathematical Society
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    • v.23 no.3
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    • pp.571-588
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    • 2010
  • We introduce the Landau-de Gennes model in order to understand molecular structures in ferroelectric liquid crystals. We investigate equilibrium configurations of the governing energy functional by means of bifurcation analysis. In particular, we obtain periodic solutions of the functional, which is a signature of a rich variety of applications of ferroelectric materials.

DFT Calculated Structures and IR Spectra of the Conformers of para-Bromocalix[4]aryl Derivatives

  • Ahn, Sangdoo;Lee, Dong-Kuk;Choe, Jong-In
    • Bulletin of the Korean Chemical Society
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    • v.35 no.12
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    • pp.3514-3520
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    • 2014
  • Molecular structures of the various conformers of para-bromocalix[4]aryl derivatives 1-4 were optimized using the DFT B3LYP calculation method. The total electronic and Gibbs free energies and normal vibrational frequencies of the different structures (CONE, partial cone (PACO), 1,2-Alternate(1,2-A) and 1,3-Alternate(1,3-A)) were calculated from the four kinds of para-bromocalix[4]aryl derivatives. The B3LYP/6-31G(d,p) calculations suggested the following: 1(PACO) is the most stable among four conformers of 1; 2(CONE) is the most stable among five conformers of 2; 3(PACO) is the most stable among four conformers of 3; 4(1,3-A) is the most stable among four conformers of 4. All the most stable structures optimized by the B3LYP calculation method were in accordance with the experimental crystal structures of 1-4. The calculated IR spectra of the various conformers (CONE, PACO, 1,2-A and 1,3-A) of 1-4 were compared.

Poly(methyl methacrylate-co-styrene)/Silicate Nanocomposites Synthesized by Multistep Emulsion Polymerization

  • Park, Yeong-Suk;Kim, Yoon-Kyung;Chung, In-Jae
    • Macromolecular Research
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    • v.11 no.6
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    • pp.418-424
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    • 2003
  • Exfoliated poly(methyl methacrylate-co-styrene) [P(MMA-co-ST)]/silicate nanocomposites were synthesized through a multistep emulsion polymerization. The methyl methacrylate monomers were polymerized first and then the styrene monomers were polymerized. The nanocomposites had core-shell structures consisting of PMMA (core) and PS (shell); these structures were confirmed by $^1$H NMR spectroscopy and TEM, respectively. P(MMA-co-ST) copolymers showed two molecular weight profiles and two glass transition temperatures (T$_{g}$) in GPC and DMA measurements. At 30 $^{\circ}C$, the nanocomposites exhibited 83 and 91 % increases in their storage moduli relative to the neat copolymer because the silicate layers were dispersed uniformly in the polymer matrix.x.