• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1000-1007
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• 2011

Wheel and rail wear is a fundamental and complicate problem in railway field. The life of railway is usually limited by wear. The wheel surface is subjected to high normal and tangential contact stress. The removal of material from the surface by wear is function of the sliding and contact stress. In the present paper, the wear characteristic depended on slip rate, contact pressure and temperature are investigated and is used to twin disc tester. The result shows that the wear in wheel-rail interface is remarkably depended on slip rate and contact pressure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.533-538
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• 2001

The barrier height is found to increase from 0.25 to 0.690 eV for Schottky contacts on n-InGaAs using deposition of Ag on a substrate cooled to 77K(LT). Surface analysis leads to an interface model for the LT diode in which there are oxide compounds of In:O and As:O between the metal and semiconductor, leading to behavior as a metal-insulator-semiconductor diode. The metal film deposited t LT has a finer and more uniform structure, as revealed by scanning electron microscopy and in situ metal layer resistance measurement. This increased uniformity is an additional reason for the barrier height improvement. In contrast, the diodes formed at room temperature exhibit poorer performance due to an unpassivated surface and non-uniform metal coverage on a microscopic level.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.178-178
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• 1999

Low temperature Si epitaxy can provide flexibility for a device designer to tailor or optimize the device performance. It is better method for controlling the doping thickness, concentration and profile than ion implantation and diffusion. But there is a limited growth thickness in this method. At a given temperature, the film grows epitaxially for a certain limiting thickness(hepi) and becomes amorphous. The transition from crystalline Si to amorphous Si is abrupt. In this study, Si film was deposited by ion beam sputter deposition on Si (0001) above a limiting thickness and measure the strain in the interface between crystalline Si and amorphous Si. The strain was compressive and the maximum value was about 2%.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.118.2-118.2
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• 2017

Combustion behavior of Fe, CuO, NiO, ZnO and $Fe_2O_3$ powder mixture was carried out by finite element method (FEM) to understand a reaction at iron and metal oxide interface. The FEM was done by using ANSYS Fluent 17.0. Initial and boundary conditions are 1 atmosphere, room temperature, 0.1MPa of oxygen partial pressure, $T_{S1}=1127^{\circ}C$, $T_{S2}=327^{\circ}C$ for a cylindrical shape specimen with dia. $35{\times}80$ [mm]. The maximum combustion temperature is $1537^{\circ}C$ for the condition of conduction, convection and radiation. The combustion temperature and rate are about $847^{\circ}C$ and 3.9mm/sec, respectively. The combustion wave is enough to make ternary ferrite phase like $CuNiZnFe_2O_3$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.137-137
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• 2015

The purposed of this work was to observe hydroxyapatite precipitation phenomena on micro-pore formed Ti-Nb alloy by PEO technique. The Ti-30Nb and Ti-30Ta alloys were remelted at least ten times in order to avoid inhomogeneity, and then cylindrical specimens (diameter 10 mm, thickness 4 mm) were cut by using laser from cast ingots of the Ti alloys. Heat treatment was carried out at $1050^{\circ}C$ for 2 h for homogenization in argon atmosphere. The morphologic change of the alloys were examined by X-ray diffractometer (XRD) and field emission scanning electron microscopy (FE-SEM).

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1737-1739
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• 1998

The paper presents experimental results of Partial Discharge(PD) in Gas Insulated Switchgear(GIS), obtained using a computer-aided PD measurement system. Different discharge sources are simulated and identified. These included internal, interface, surface and protrusion. For internal discharge, it showed symmetrical discharge type between positive and negative cycle. Interface discharge showed smaller number and higher peak than internal discharge but symmetrical discharge as well. For surface discharge, it showed small number and high peak in positive half cycle but large number and low peak in negative half cycle. For protrusion discharge, small number and high peak of discharge were shown only in negative half cycle.

• Korean Membrane Journal
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• v.1 no.1
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• pp.100-105
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• 1999

A novel system to thicken the concentrated colloidal solution from membrane water treat-ment processes was developed. A hollow-fiber microfilter(hydrophilic polyethylene nominal pore size 0.1 ${\mu}$m total surface area 0.42 m2) was installed in an acrylic housing that has an aeration port 5 cm below the membrane and a clarifier in the bottom. The concentrate was uniformly supplied from the top of the housing. Bacuum filtration caused downward flow of concentrate and as a result thickening interface. The addition of poly-aluminum chloride (PAC) resulted in rapid increase of trans-membrane pressure (TMP) and in no improvement of the filtered water turbidity and thickening process. Two types of con-centrate and concentrate turbidity had little effect on the increase of TMP and concentrate thickening. It was observed that for the same height of membrane housing membrane surface area to housing volume (A/V) ratio had significant effect on the increase of TMP. When the housing volume was increased ten times the increasing rate of TMP was three times faster as compared to the original housing. A hydraulic model successfully simulated the formation and sedimentation of thickening interface.

• Archives of Pharmacal Research
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• v.2 no.2
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• pp.85-88
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• 1979

Data on the solubility of p-hydroxy-benzoate in amide-water cosolvent system and surface tension of the binary amide-water cosolvents are analyzed in terms of the possible mechanism for cosolvency. The results of the study suggest that strong partitioning of the alkylated amides to the ester surface, thus reducing the hydrophobic interface within the system, nay account for much of the cosolvency phenomena observed in these systems.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.1
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• pp.1-10
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• 2011

Nonlinear harmonic waves generated at cracked interfaces are investigated both experimentally and theoretically. A compact tension specimen is fabricated and the amplitude of transmitted wave is analyzed as a function of position along the fatigued crack surface. In order to measure as many nonlinear harmonic components as possible a broadband Lithium Niobate ($LiNbO_3$) transducers are employed together with a calibration technique for making absolute amplitude measurements with fluid-coupled receiving transducers. Cracked interfaces are shown to generate high acoustic nonlinearities which are manifested as harmonies in the power spectrum of the received signal. The first subharmonic (f/2) and the second harmonic (2f) waves are found to be dominant nonlinear components for an incident toneburst signal of frequency f. To explain the observed nonlinear behavior a partially closed crack is modeled by planar half interfaces that can account for crack parameters such as crack opening displacement and crack surface conditions. The simulation results show reasonable agreements with the experimental results.

• Journal of Welding and Joining
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• v.12 no.3
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• pp.48-55
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• 1994

In this experiment, to find optimum brazing conditions for Cu/Stainless Steel brazing using filler metals of Ag-Cu-Zn-Cd system, first of all spreading ratio was tested on 304 stainless Steel and low carbon steel. And then shear test of brazed joint was executed. As the result of that, the shear strengths of brazed joints were the range of 60-90 MPa. Through microstructure analysis for brazed interface layer, We found as follows. Firstly interface layer increased as time increased. Secondly continuous layer of Ag-Cd compound was observed along the side of stainless steel. Also by means of EDS analysis for fracture surface, ductile fracture was occurred and precipitates on the fracture surface were found to include Cr, Mn, Si in Ag-rich phase.