• Journal of the Korean Ceramic Society
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• v.24 no.6
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• pp.572-578
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• 1987

The vacuum evaporated Au films on soda-lime glasses were measured by the electrical conductivity with the variation of the annealing time, relative humidity, and temperature. Au films structures were observed by scanning Electron Microscope and X-ray Diffractometer. As the annealing time and temperature increased, the electrical conductivity was increased due to the migration or annihilation of defects, but the electrical conductivity was decreased as with the relative humidity increased. Au films by XRD and SEM examination showed the negligible effect of chemical reactions.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.101-110
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• 1987

The relative electrical conductivity of vacuum deposited Al films on a soda-lime(2947) and an alumino boro silicate(7809) glass was investigated with the variation of the relative humidity,temperature and film thickness. The structure and microstructure of Al films before and after exposure to the humidity wereexamined by the X-ray Diffractormenter(XRD) and Scanning Electron Microscope(SEM). As the relative humidity increased, the electrical conductivity of Al films on both glasses was decreased. However, the Al films on 7809 glass showed higher conductivity than that of 2947 glass under the same testing conditions. The decreasing of electrical conductivity was caused by the formation of Aluminum hydroxide which was made by the reaction between the aluminum films and water vapor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.101-102
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• 2007

In order to characterize an electrical conductivity of ${\lambda}$-DNA by relative humidity, I-V characteristics through DNA on Au electrode with $1{\mu}m$ gap were measured as a function of the relative humidity. The electrical conductivity increased and the resistance decreased with an increase of humidity. The maximum effect of the humidity on the electrical property of DNA was obtained with the range from 43 to 82%. The hysteresis loop in I-V characteristics of DNA was disappeared above 92% of the humidity while the applying voltage was changed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.85-93
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• 1988

This laboratory study was carried out in order to produce fundamental data for analyzing salt movement and desalinization effects, using samples of silt loam soil collected in Gyehwado and Daeho reclaimed tidelans, and samples of silty clay loam soil collected in Kimie tideland. Desalinization experiments with gypsum treatment were performed to analyze changes of the hydraulicc conductivity with changes of the soil property and the salt concentration during the desalinization of reclaimed tideland soils by leaching through the subsufface drainage, and correlations between factors infl uencing the reclamation of salt affected soils were analyzed by the statistical method. The results were summarized as follows: 1. The reclaimed tideland soils used in this study were saline-sodic soils with the high exchangeable sodium percentage and the high electrical conductivity. 2. Changes of the hydraulic conductivity with the amount of leaching water and the leaching time elapsed were affected by the amount of gypsum except exchangeable sodium and clay contents. The regression equation between the depth of water leached per unit depth of soil (Dw / Ds : X) or the square root of the leaching time elapsed (T $^1$ $^2$ : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a . bx. 3. The more exchangeable sodium and clay contents regardless of the amount of gypsum, the more the leaching time was required until a given volume of water was leached through the soil profile. The regression analysis showed that the relationship between the depth of water leached per unit depth of soil(Dw /Ds:X) and the square root of the leaching time elapsed(T$^1$$^2$ :Y) could be described by Y=a . Xb. 4. The hydraulic conductivity was influenced to a major degree by the salt concentration provided that the electrical conductivity was below 10 mmhos / cm during the desalinization of reclaimed tideland soils. The regression equation between the relative electrical conductivity ( ECr : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a + b . X-$^1$. 5. In conclusion, the hydraulic conductivity, leaching requirements and the leaching time elapsed can be estimated when the salt concentration decreases to a certain level during the desalinization of reclaimed tidelands, and the results may be applied to the analysis of salt movement and desalinization effects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.22-24
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• 1995

The electrical conductivity of TiO$_2$doped ZnO was investigated by means of complex impedance measurement and voltage-current source and meaurement unit. The e1ectrical conductivity of TiO$_2$added ZnO was increased with increasing the concentration of TiO$_2$. The calculated relative dielectric constant was decreased with increasing the concentration of TiO$_2$. The increase of electrical conductivity seems to be the effect of TiO$_2$donor doping.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.96-105
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• 1989

This laboratory study was performed to produce basic data for the estimation of water requirements for desalinization, through analyzing changes of the electrical conductivity and the exchangeable sodium percentage during the desalinization of reclaimed tidelands. Desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The results obtained from this study were summarized as follows : 1. The sample soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. Changes of the electrical conductivity and the exchangeable sodium percentage with water requirements for desalinization showed a similar tendency in the desalinization experiment by the same water management practice. 3. The regression equation between the relative electrical conductivity(EC/EC) and water requirements for desalinization(Dw/Ds) could be described by Dw/Ds=O. 29x(EC/EC.) -0.982 (Leaching method), Dw/Ds=3. 678X0. 030(EC/EC ) (Rinsing method). 4. The regression equation between the relative exchangeable sodium percentage (ESP/ESP ) and water requirements for desalinization (Dw/Ds) could be expressed in Dw/Ds = 0.039 x (ESP/ESP. ) - 1. 134 (Leaching method), Dw/Ds=7. 197X0. 024(ESP/ESP ) (Rinsing method). 5. It was estimated that water requirements for the adequate desalinization would be Dw/Ds=0.3 (Leaching method) and Dw/Ds=3.0 (Rinsing method)

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.2
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• pp.68-72
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• 2004

The performance of copper-tungsten for electrodes used in an ultra high voltage interruption system was evaluated by means of an interruption test, which requires a large-scale apparatus and high cost. In this study, prior to the interruption test, the characteristics of a Cu-W electrode were estimated through the DC arc test, which is a simple, low cost procedure. The DC arc characteristics of a 20wt%Cu-80wt%W electrode were investigated with the change of tungsten powder size distribution and the addition of nickel. In specimens containing a high volume fraction of large sized tungsten particles, the relative density and hardness of sintered Cu-W electrodes increased while the electrical conductivity and the DC arc resistance decreased. Furthermore, the relative density became enhanced with the increase of the amount of nickel while the hardness and electrical conductivity diminished and the DC arc resistance worsened.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.123-132
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• 1987

Yttria-stabilized zirconia with erbia-lanthana were investigated with respect to the amount of Ln2O3 (Ln; Er, La) addition in the range of 0.5∼5 mol% to the base composition of 8 mol% yttriazirconia. Following analysis and measurement were adopted for the characterization of synthesizes of solid electrolyte; phase transformation, lattice parameter, crystallite size, relative density, chemical composition and SEM/EDS. Electrical conductivity by two-probe method versus temperature from 350$^{\circ}C$ to 800$^{\circ}C$ and frequency in the range of 5Hz∼13MHz by complex impedance method was also conducted together with the determination of oxygen ion transference number by EMF method for the evaluation of their electrical properties. The results were as followsing; Electrical conductivity were decreased with increase in Ln2O3 content, but their activation energies increased. In the case of La2O3 addition, espicially, its electrical conductivity was decreased owing to the segregation of second phases at the grain-boundary. Grain-boundary conductivity of the specimen contained 0.5 mol% Er2O3 exhibited a maximum conductivity among thecompositions experimented. However, their bulk conductivities decreased in both case. Oxygen ion transference number was also reduced with decrease in oxygen partial pressure. For example, in the case of Er2O3 addition it retained value in the range of 0.97∼0.94 abvove 4.74${\times}$10-2in oxygen partial pressure. With the increase in the quantities of the evaporation of additive components, the crystallite size of stabilized zirconia decreased, and their relative density also reduced owing to the formation of porosity in their matrices. In the case of La2O3 the sinterbility was improved in the limited amount of addition up to 0.5 mol%, in the same range of addition the strength of sintered bodies were improved perhaps owing to the precipitation of metastable tetragonal phase in the fully stabilized zirconia.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.347-349
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• 1999

We have fabricated insulating thin films using p-hexadecoxyphenol(p-Hp) that was formed phenol-formaldehyde resin of crosslinked structure from reaction with formaldehyde by LB technique. For fabricated MIM device, the possibility for insulating layers of electronic were investigated by electrical properties of their LB films according to crosslinking of LB films current-voltage (I-V) properties and frequency-capacitance (C-F) characteristics. We have provided evidence for the high insulating performance of phenol-formaldehyde thin films by the LB method. Conductivity of their LB films was as follows: pure water > 1 % aq. Formaldehyde > heat treatment, in the current-voltage (I-V) characteristics. It is demonstrated that insulation properties of crosslinked p-HP LB films were improved. In capacitance-frequency properties, the heat-treated p-HP LB films for crosslinking showed a low relative dielectric constant.

• Korean Journal of Materials Research
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• v.21 no.8
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• pp.456-460
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• 2011

Microelectromechanical systems (MEMS)-fabricated suspended devices were used to measure the in-plane electrical conductivity, Seebeck coefficient, and thermal conductivity of 304 nm and 516 nm thick InGaAlAs films with 0.3% ErAs nanoparticle inclusions by volume. The suspended device allows comprehensive thermoelectric property measurements from a single thin film or nanowire sample. Both thin film samples have identical material compositions and the sole difference is in the sample thickness. The measured Seebeck coefficient, electrical conductivity, and thermal conductivity were all larger in magnitude for the thicker sample. While the relative change in values was dependent on the temperature, the thermal conductivity demonstrated the largest decrease for the thinner sample in the measurement temperature range of 325 K to 425 K. This could be a result of the increased phonon scattering due to the surface defects and included ErAs nanoparticles. Similar to the results from other material systems, the combination of the measured data resulted in higher values of the thermoelectric figure of merit (ZT) for the thinner sample; this result supports the theory that the reduced dimensionality, such as in twodimensional thin films or one-dimensional nanowires, can enhance the thermoelectric figure of merit compared with bulk threedimensional materials. The results strengthen and provide a possible direction in locating and optimizing thermoelectric materials for energy applications.