• Bulletin of the Korean Chemical Society
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• v.5 no.4
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• pp.162-167
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• 1984

Equilibrium and dynamical behaviors of an n-alkane poymer (decane) in solution have been investigated by a molecuar dynamics simulation method. The polymer is assumed to be a chain of elements $(CH_2)$ interconnected by bonds having a fixed bond length and bond angle, but esch bond of the polymer is allowed to execute hindered internal rotation. The calculation explicitly considers the molecular naturer of solvent by including the intermolecular interactions between slovent-solvent molecules and chain element-solvent molecule. We present the results of calculations on (1) equilibrium properties (the solvent molecule-chain element pair correlation function, chain element-chain element pair correlation function, the mean square end-to-end distance and the mean square radius of gyration of the polymer) and (2) dynamic properties (four different autocorrelation functions, namely, the autocorrelation functions for the end-to-end distance and the radius of gyration, and the velocity autocorrelation functions for the center of mass and the end point of the chain). We found that the physical properties of the polymer chain depends sensitively on temperature. Comparison of the present work with other authors' results is also presented.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.423-427
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• 2010

Carbon nano sphere(CNS) and nano bowl of carbon(NBC) containing 1.0 wt% copper were prepared by impregnation method and their catalytic activity was compared in the phenol hydroxylation with hydrogen peroxide in the presence of water and acetonitrile as a solvent, respectively. Cu content of catalysts was determined by EDS, and BET, pore volume, pore size and pore size distribution were compared. For both catalysts, phenol conversion, $H_2O_2$ efficiency and yield of catechol and hydroquinone were higher in the presence of water as a solvent than those in the presence of actonitrile. And catalytic activity such as phenol conversion and $H_2O_2$ efficiency of 1.0 Cu/CNS is about two times higher than that of 1.0 Cu/NBC in water solvent.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.383-389
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• 2008

This study was performed to compare effect of immune activities of Rhodiola sachalinensis by various extraction process with different temperature and extraction solvents. Experiments were performed for investigate the immune activities on human B and T cell growth and secretion of their cytokines. Also, antibodies in serum were investigated in female ICR mouse by feeding the extracts of R. sachalinensis at doses of 40, 120 and 360 mg/kg orally for 15 days. The immune cell growth and secretion of cytokines (IL-6, TNF-$\alpha$) on human B and T cells were increased by adding R. sachalinensis extracts compare to the control. Also, total serum IgG levels increased by feeding R. sachalinensis extracts. It can be conclude that optimum condition for efficient extraction of R. sachalinensis as functional material is slovent extraction process using water with ultrasonification at below $100^{\circ}C$ than typical process.