• Journal of the Korean institute of surface engineering
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• v.35 no.2
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• pp.107-112
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• 2002

We have studied diffusion behavior of NiFe/Ag bilayer deposited by on silicon Ion Beam Sputtering methods. The diffusion behavior of NiFe and Ag in NiFe/Ag thin film is analyzed by Medium Energy Ion Scattering Spectroscopy. For samples without Ta underlayer, silicides such as Ni-Si or Fe-Si were formed at Si substrate and NiFe interface. In contrast, Ag predominantly diffused into the NiFe layer probably through their grain boundaries for Ta underlayered samples.

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.49-56
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• 2000

In the present we.k, temperature dependence of oxygen diffusivity in the polyvinyl chloride (PVC) film $D_f$ formed on gold electrode was investigated using steady-state rotating disk electrode (RDE) technique and modulated electrohydrodynamic (EHD) impedance technique. Both the diffusion rate defined as the ratio of oxygen diffusivity in the PVC film to the film thickness $D_f/\delta_f$ and the time constant $\delta_f^2/D_f$ for oxygen diffusion through the PVC film were obtained from plot of the limiting current versus disk rotation speed and from filing the EHD impedance spectra experimentally measured to those theoretically calculated on the basis of the diffusion equation for mass transport through the non-conductive and porous film, respectively. By combining measured $D_f/\delta_f$ with $\delta_f^2/D_f$, we determined $\delta_f\;and\;D_f$ at room temperature separately. As temperature increased, it appeared that the $D_f$ value measured for the PVC film-covered gold RDE was enhanced more rapidly than that $D_s$ value in the solution measured for the PVC film-free gold RDE. This means that the pores glowing with increasing temperature act as effective diffusion paths within the film. The present in-situ steady-state and modulated EHD measurements prove to be effective for determining $\delta_f\;and\;D_f$, separately and at the same time the porosity of the PVC film at temperatures below glass temperature $T_g$ of the film.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.221-221
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• 2009

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.886-891
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• 1995

Electroactive monolayers based on zirconium(Ⅳ) phosphonate film were prepared on gold and tin oxide electrodes by sequential layer-by-layer depostion technique. High transfer coefficient values and surface coverages of surface bound redox molecules were obtained from the electrochemical measurements of heterogeneous electron transfer rates for monolayer modified electrodes. 1,10-Decanediylbis(phosphonic acid) (DBPA) monolayer as insulating barrier was effective in blocking electron transfer. However, these film modified oxide electrode shows voltammetric behavior of diffusion/permeation process taking place at very small exposed area of modified electrode through channels due to structural defects within film when a very fast redox couple such as Ru(NH3)63+ is hired.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1584-1589
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• 2003

This work applies the equilibrium molecular dynamics simulation method to study a Lennard-Jones liquid thin film suspended in the vapor and calculates diffusion coefficients by Green-Kubo equation derived from Einstein relationship. As a preliminary test, the diffusion coefficients of the pure argon fluid are calculated by equilibrium molecular dynamics simulation. It is found that the diffusion coefficients increase with decreasing the density and increasing the temperature. When both argon liquid and vapor phases are present, the effects of the system temperature on the diffusion coefficient are investigated. It can be seen that the diffusion coefficient significantly increases with the temperature of the system.

• Journal of Welding and Joining
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• v.32 no.5
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• pp.13-20
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• 2014

A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.

• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.149-152
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• 1991

We report a new method of fabricating a Ti:LiNb03 waveguide with no out-diffusion by coating the waveguide with $SiO_2$ thin film. It was coated before diffusion process, and the $LiO_2$ out-diffusion was prevented in the diffusion process. We compare the near field patterns of the guided modes between the typical waveguide and the waveguide fabricated by new method proposed here.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.503-508
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• 1999

We have investigated the physical and diffusion barrier property of Ti-Si-N film for Cu metallization. The ternary compound was deposited by using reactive rf magnetron sputtering of a TiSi$_2$target in an Ar/$N_2$gas mixture. Resistivities of the films were in range of 358$\mu$$\Omega$-cm, to 307941$\mu$$\Omega$-cm, and tended to increase with increasing the $N_2$/Ar flow rate ratio. The crystallization of the Ti-Si-N compound started to occur at 100$0^{\circ}C$ with the phases of TiN and Si$_3$N$_4$identified by using XRD(X-ray Diffractometer). The degree of the crystallization was influenced by the $N_2$/Ar flow ratio. The diffusion barrier property of Ti-Si-N film for Cu metallization was determined by AES, XRD and etch pit by secco etching, revealing the failure temperature of 90$0^{\circ}C$ in 43~45at% of nitrogen content. In addition, the very thin compound (10nm) with 43~45at% nitrogen content remained stable up to $700^{\circ}C$. Furthermore, thermal treatment in vacuum at $600^{\circ}C$ improved the barrier property of the Ti-Si-N film deposited at the $N_2$(Ar+$N_2$) ratio of 0.05. The addition of Ti interlayer between Ti-Si-N films caused the drastic decrease of the resistivity with slight degradation of diffusion barrier properties of the compound.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.1 s.307
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• pp.17-26
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• 2006

The error diffusion method is one of the digital halftoning processes that transforms the continuous-tone image to the binary image and the method has the excellent reproduction ability. However the error diffusion method using the permanent threshold has difficulty in proper binarization, so the method has the periodic pattern and is unpleasant to the eye. In this paper, to reduce defects and to binarize properly, we propose the error diffusion method using the adaptive threshold. Depending on the intensity distribution of the input gray scale image, we decided on the adaptive threshold with the average of the intensities. The error diffusion method with the adaptive threshold has the better performance than the existing method and is evaluated with experiments and comparisons.

• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.64-68
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• 2009

It has been observed that coated steel structures deteriorate more rapidly than the designed lifetime due to acid rain caused by air pollution, etc. Therefore, improving the corrosion resistance of anti-corrosive paint is very important in terms of safety and the economic point of view. In this study, the corrosion resistance of five kinds of anti-corrosive paints, including the Acryl, Fluorine, and Epoxy resin series, were investigated with electrochemical methods, such as corrosion potential measurements, polarization curves, diffusion limiting current density, etc. As a result, the corrosion resistance of the F101 specimen with the fluorine resin series was found to be superior to the other specimens, while E100 with the epoxy resin series also showed a somewhat good corrosion resistance. Furthermore, it was observed that the amount of water and oxygen entering the inner side of a painted film increased with an increase in immersion time, irrespective of the kind of resin series. However, the oxygen diffusion limiting current density of a specimen with good corrosion resistance was relatively decreased compared to other specimens, because of the difficulty of oxygen diffusion penetrating to the inner side of the film. Consequently it is suggested that we can qualitatively evaluate the corrosion resistance of an anti-corrosive paint by measuring the diffusion limiting current density as an electrochemical method.