• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.159-159
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• 2010

We conducted bum-in test by current stress to evaluate acceleration reliability characteristics about p-resistivity influence of GaN-based light-emitting diodes. The LEDs used in this study are the polarization field-induced LED(PF-LED) having low p-resistivity and the highly resistive LED(HR-LED) having high p-resistivity. The result of high stress experiment shows that current crowding phenomenon is occurred from the center of between p-bonding pad and n-bonding pad to either electrodes. In addition, series resistance and optical power decrease dramatically. These results means that the resistance of between p-bonding pad and p-GaN affect reliability. That's why we need to consider the ohmic contact of p-bonding pad when design the high efficiency and high reliability LEDs.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.237.1-237.1
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• 2011

Resistivity of GaN has been investigated under the influence of ion implantation. n-type, p-type and also undoped GaN has been used here. A ring shape pattern of Au was fabricated on GaN film by the photolithography technique. H, He and Ar were used for implantation. The ion implantation energy, fluence and post-implant annealing temperature varied in this research. Because of the making barrier in some selected area using ions, the resistivity changed in all the samples with the change of both fluence and energy. At room temperature, the resistivity of n-type GaN has been increased from $1.9{\times}10-2$ to $17.7{\times}10-2\;{\Omega}-cm$. This is high for He ion. But undoped and p-type GaN showed some anomalous character.

• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.969-976
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• 1996

RuO2 thin films were deposited on SiO2(1000 $\AA$)/Si by hot-wall Metal Organic Chemical Vapor Depositon. The crystallinity of RuO2 thin films increased with increasing deposition temperature and the preferred orienta-tion of RuO2 films converted (200) plane to (101) plane with increasing film thicknesses. Such a change in preferred orientation was influenced on the crystallographic structure and the residual stress of RuO2 thin films. The resistivity of the 2700$\AA$-thick RuO2 thin films deposted at 30$0^{\circ}C$ was 52.7$\mu$$\Omega$-cm and they could be applicable to bottom electrodes of high dielectric materials. However the resistivity of RuO2 thin films increased with decreasing film thicknesses. The grain size and the resistivity of RuO2 thin films were densified with increasing the annealing temperature and showed the decrease of resistivity.

• Corrosion Science and Technology
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• v.5 no.3
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• pp.90-93
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• 2006

Prevention of crevice corrosion was studied for STS 304 stainless steel using a Mg-alloy galvanic anode in solutions with various specific resistivity. The crevice corrosion and corrosion protection characteristics of the steel was investigated by the electrochemical polarization and galvanic corrosion tests. Experimental results show that the crevice corrosion of STS 304 stainless steel does not occur in solutions of high specific resistivity, but it occurs in solutions of low specific resistivity like in solutions with resistivities of 30, 60 and $115{\Omega}{\cdot}m$. With decreasing specific resistivity of the solution, the electrode potential of STS 304 stainless steel in the crevice is lowered. The potential of STS 304 stainless steel in the crevice after coupling is cathodically polarized more by decreasing specific resistivity indicating that the crevice corrosion of STS 304 stainless steel is prevented by the Mg-alloy galvanic anode.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.6
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• pp.331-337
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• 2010

Aluminum nitride (AlN) thin films containing various amounts of Co content have been deposited by using a two-facing targets type sputtering (TFTS) system. The deposited films were also annealed successively and isothermally at different temperatures. Annealing treatment can control the physical properties as well as the microstructure of AlN films with Co particles. High magnetization and high resistivity are obtainable in AlN films containing dispersed Co particles. The coercivity of the films does not depend on annealing time, but it increases with increasing annealing temperature due to the increase of the grain size. A high saturation magnetization of 46 kG and resistivity of 2200 ${\mu}{\Omega}$-cm was obtained for AlN films containing 25 at% Co.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.65-70
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• 2005

A low resistivity zone is found in many places such as a fractured fault zone, weathered zone and aquifer. The electrical resistivity is influenced mainly by pore fluid as well as the clay mineral types and contents, Hence, it is very important to understand the relationship between the electrical resistivity and clay contents associated with the low resistivity zone for geotechnical applications such as civil engineering. This study examines the characteristics of clay mineral types and contents to electrical resistivity through sample measurements, and proposes an expression relating the resistivity and clay content. The electrical resistivity is measured for an artificial agar specimen with clay minerals instead of a natural rock. The clay minerals used are Kaolinite and Montmorillonite. Montmorillonite shows remarkably lower resistivity than Kaolinite, although its clay content is fewer than that of Kaolinite. Also, the proposed expression shows a good correlation coefficient as high as 0.89 or more in all clay minerals.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.27-33
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• 2014

Electrical resistivity of concrete can be measured in a more rapid and simple way for estimating durability of the concrete, however, carbonation causes a result of misleading for durability testing because carbonation leads to a significant reduction in the permeability and porosity of concrete. The purpose of this study is to estimate and quantify the effect of carbonation of concrete on a surface electrical resistivity measurement. Samples of three mixes with difference w/c were prepared and exposed in a carbonation chamber for 330 days. The results show that carbonation leads high electrical resistivity. The increase is substantial and has been shown to proportional to the extent of the carbonation by some of extent. The relationship between electrical resistivity and carbonation depth is taken in the study. Resistivity ratio of carbonated concrete to air concrete decreased significantly from the specific carbonation depth, however, resistivity ratio of carbonated concrete to air concrete had a linear relation with carbonation depth. From the relationship between electrical resistivity and carbonation depth, it is expected that the result should be subsequently used as a calibration curve for estimating carbonated concrete to overcome the interruption effect of carbonation on regular measurements of the electrical resistivity.

• 전기의세계
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• v.21 no.1
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• pp.17-21
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• 1972

Electrical resistivity and switching phenomena in glass semiconductor of AsTe and AsTeGa is studied. Samples sliced from ingot which is air quenched or water quenched, show high resistivity at room temperature. The resistivity of the AsTe and AsTeGa is 1*10$^{6}$ .ohm.-cm and 5*10$^{6}$ .ohm.-cm at 27.deg. C. Switching phenomena take place in thin the thick samples. Holding voltage is different with the thickness of the samples and the characteristics of switching in the thin and thick samhles are similar. When square wave pulse voltage is applied, delay time is detected to 5.mu.sec by oscilloscpoe.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.216-217
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• 2007

In this paper we investigated the volume resistivity and AC conduction current according to the temperature and voltage. As a result, the volume resistivity comes to be small according to the measurement temperature and voltage. AC conduction current of the heat treatment specimen is increased because of the decrease of insulation.

• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.130-135
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• 2004

This paper describes the physical properties of the factors controlling the electrical resistivity of the subsurface. Resistivities of various types of soil and rock samples saturated with sodium chloride solutions having nine different concentrations were measured, and the measured resistivities of these samples were compared with calculated resistivities obtained using the conventional empirical formulas. From the results obtained, we observed that the resistivity of the soil and rock samples increases with increasing in pore-fluids resistivity regardless of the media type. However, between 20 and 200 ohm-m, which is the normal range of resistivity of groundwater, the resistivity of the pore-fluids have little or no effect on the resistivities of the samples used. Below 10 ohm-m, the resistivities of the samples are mainly controlled by the pore-fluids, whereas, in the normal range of resistivity of groundwater, the sample resistivities are controlled by their intrinsic matrix resistivity more than by the pore-fluids resistivity. Also, the measured resistivity of rock and soil samples having more than $20\%$ clay contents showed a good agreement with the calculated resistivity using the parallel resistance model whereas, the calculated resistivities of glass beads correlate with that obtained using Archie's formula. When the pore-fluid resistivity is high, the computation of the resistivity values of the samples using the Archie's formula could not be carried out. Through this study, we were able to confirm that the tests are only applicable to the parallel resistance model considering the intrinsic matrix resistivity within the normal resistivity range of groundwater in the subsurface.