• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.80-83
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• 1961

Solution of the diffusion problem applicable to steady state reduction at the ideal streaming mercury electrode are presented, with special attention being given to the influence of stream contraction caused by the gravity. To eliminate the convection occurring in the layer between the streaming mercury and the electrolytic solution, a new method have been invented, in this case the solution being tested was streamed with same velocity of the streaming mercury. Experiment have been made in order to compare the experimental value with the theoretical value and the experimental diffusion current was approached more to the theoretical value than the value obtained by earlier form of the streaming mercury electrode used by Heyrovsky.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.217-220
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• 2004

Metakaolin is a cementitious material for producing high-strength concrete. This material is now used as substitute for silica-fume. In this paper, we did the durability test such as chloride ion diffusion, chemical attack. repeated freezing and thawing, carbonation. In the chloride ion diffusion test, according to the increase of substitute of metakaolin & silica-fume for binder, the diffusion coefficient is more reduced. And in the chemical attack test, according to the increase of substitute, the resistance is more excellent. In the other durability test, the concrete using metakaolin is also compared with those of the portland cement concrete and silica fume concrete. According to these tests, we recognized that metakaolin is able to be used as a substitute for silica-fume.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.169-169
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• 2000

최근 반도체 소자의 초고집적화 현상에 따라 기존의 Al-base 합금에 대한 한계에 달하면서 그에 대한 대체 물질로 Cu가 관심을 모으게 되었고 그럼으로써 Cu metallization을 위한 많은 연구가 진행되어 왔다. Cu는 Al-base 합금계보다 비저항이 낮고, 녹는점이 높으며, 또한 electromigration 특성이 뛰어난 것으로 알려져 있다. 공학적인 면에서 이미 이들 계에 대한 adhesion 및 전기적 특성에 대한 많은 연구가 있어왔지만, 이들 특성 변화에 대한 물리적 의미를 제공할 만한 기초 자료들이 부족한 상태이다. 본 연구에서는 부도체인 polyimide 박막과 diffusion barrier인 TiN 박막위에서의 Cu 박막성장에 따르는 interface chemical reaction의 변화를 XPS를 이용하여 관찰함으로서 이들 계에 있어서의 adhesion과의 관계를 조사하였다. 그리고 XPS를 이용한 modified surface accumulation method를 적용시켜 TiN diffusion barrier를 통한 Cu의 grain boundary diffusion 상수들을 측정하였다. Cu/TiN system의 경우에는 interface chemical reaction이 일어나지 않았지만 Cu/polymide system에 있어서는 boundary diffusivity는 특히 40$0^{\circ}C$에서 $650^{\circ}C$ 영역에서, Db=60$\times$10-11exp[-0.29/(kBT)]cm2/sec 이었다.

• Bulletin of the Korean Chemical Society
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• v.6 no.3
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• pp.128-131
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• 1985

A series of copolymer membranes of 2-hydroxyethylmethacrylate (HEMA) with selected hydrophobic monomers were prepared without crosslinking agents. The equilibrium water content, the partition coefficient, and the permeability of the solutes such as urea, methylurea, 1,3-di-methylurea, and acetamide via these membranes were measured. The partition coefficient data show that as the hydrophobicity of solutes increased, the partition of solutes were dictated by hydrophobic interaction between solute and polymer matrix. Diffusion coefficients obtained in these experiments decrease as the water content of polymer membrane decreases. This decrease is blunt as the excess heat capacities, ${\phi}C^0_p$ (excess) in aqueous solution at infinite dilution of solute increases. To investigate the relationship between water content and diffusion coefficient, the results of the diffusion experiments were examined in light of a free-volume model of diffusive transport. The remarkable increase of urea mobility in the polymer network containing relatively larger bulk water can be considered as water structure breaking effect.

• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.430-433
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• 1989

Molecular reorientation of oblate symmetric top molecules in the presence of internal rotation is investigated and an analytic expression for the spin-rotational relaxation rate of a nucleus attached to the internal rotor is obtained as a function of the internal angular momentum correlation time. The overall reorientation of the symmetric top is treated by the anisotropic rotational diffusion and the internal rotation is assumed to undergo modified extended rotational diffusion. The result is compared with the previous work for the prolate symmetric top molecule and it is shown that both results reduce to the same expression in the spherical top limit.

• Bulletin of the Korean Chemical Society
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• v.12 no.5
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• pp.468-473
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• 1991

Viscoelastic properties of PET filament fibers on stress relaxation were investigated in the solvents of $H_2$O, 0.05% NaOH and 50% DMF using an Instron (UTM4-100 Tensilon) with solvent chamber. The theoretical stress relaxation equation derived by applying the Ree-Eyring's hyperbolic sine law to dashpot of three element non-Newtonian model was applied to the experimental stress relaxation curves, and the model parameters $G_1,G_2$, ${\alpha}$ and ${\beta}$ were obtained. By analyzing temperature dependency of the relaxation time, the values of activation entropy, activation enthalpy and activation free energy for flow in PET filament fiber were evaluated, the activation free energy being about 25.7 kcal/mol. The self diffusion coefficient and hole distance were obtained from parameters ${\alpha}$, ${\beta}$ and crystallite size in order to study the self diffusion and the orientation of crystallites in amorphous region and the effect of solvent.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.735-738
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• 2012

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3521-3523
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• 2011

• Proceedings of the Korean Vacuum Society Conference
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• 2003.08a
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• pp.146-146
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• 2003

• Bulletin of the Korean Chemical Society
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• v.15 no.10
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• pp.909-911
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• 1994