• Economic and Environmental Geology
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• v.29 no.3
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• pp.335-343
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• 1996

The dipole-dipol electrical resistivity survey was conducted to investigate the probable contamination of the Han river by leachate from the near-by Nanjido Landfill. The survey line of 3 km was set along the unpaved road toward the Han river. For the convenience of the field work, the survey line was divided into four segments. The complete two-dimensional resistivity section was constructed by connecting the inversion result of each segment. Gravity survey was also carried out along the profile parallel to the resistivity line. Near surface resistivity generally appeared to be of very low value in most part of the survey area and the boundary between the alluvium layer and underlying basement rocks is well discriminated on the resistivity section. These results agree well with those of the preceding Schlumberger depth sounding made at adjacent area by Lee and fun (1995). The variation of thickness of the alluvium layer delineated by gravity anomaly profile also correlates well with the result of the resistivity survey on the qualitative basis. The problem of contamination by leachate from the Nanjido Landfill, where various waste materials have been dumped without any proper treatment facilities, has been remains unsolved yet. Therefore, we present the most probable passages of leachate flow based on the survey results and have briefly discussed about measure for contamination control. Considering the thickness of alluvium and the possible existence of fractured zone, the middle point between 1st and 2nd landfill and the midst of 1st landfill are the most hazardous regions to make leachates flow into the Han river. Since large amounts of leachates are observed from the test wells located on the lines extending from the border between the 1st and 2nd landfill and the middle of the lst landfill, contamination protection barriers are strongly recommended near these regions.

• Membrane Journal
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• v.5 no.3
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• pp.109-118
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• 1995

In this study, cell resistivity and membrane resistivity were measured in Fe-Cr redox-fiow battery system using commercial ion-exchange membranes. Cell resistivity and membrane resistivity at charging periods are higher than at discharging periods. And at the same membrane the resistivity were increased with increasing SOC. The resistivity of hydrocarbon type Seiemion CMV membrane was smaller than perfluoro type Nafion 117 and Nafion 551. The cell resistivity and membrne resistivity of CMV membrane at 0 % SOC was $12.864\Omega \textrm{cm}^2$ and $8.751\Omega \textrm{cm}^2$, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.526-532
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• 2000

Recent studies have been directed toward obtaining a better understanding of the application of electrostatic precipitators to collect fly ash particles produced in a coal-fired power plant. Electrical resistivity can be described as the resistance of the collected dust layer to the flow of electrical current and is an important property for the collection efficiency in the electrostatic precipitator. In this paper, fly ash resistivity as a function of temperature up to $450^{\circ}C$ has been experimentally investigated using the resistivity meter consisted of the movable electrode, dust cup, and furnace. Resistivity was found to increase with increased temperature up to $200^{\circ}C$ due to the reduction of water concentration and then gradually decrease with increased temperature due to the activation of electrons. As the resistivity of fly ash in the flue gas temperature of $150^{\circ}C$ was measured >$10^{10}$ ohm cm, the efficiency of fly ash removal in the electrostatic precipitator might be expected to be low due to back-corona phenomenon. Flue gas conditioning in the electrostatic precipitator to reduce the resistivity of fly ash as required.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.464-475
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• 2009

Electrical resistivity can be used for porosity estimation. In order to improve previously developed ERCP(Electrical Resistivity Cone Probe), 4ERP(4 Electrical Resistivity Probe), which has Wenner array at the tip of probes, has been developed. In properties of current flow Wenner array measures electrical properties of undisturbed area during penetration and relatively correct measurements are guaranteed without polarization. Furthermore, Wenner array equation can estimate electrical resistivity without extra calibration. 4ERP is developed into 2 types, penetration and fixation. Penetration type has wedge-shaped tip. Considering disturbance minimization, fixed type has plane tip. Fixed type 4ERP in consolidation cell measure electrical resistivity increment along porosity decrease, and penetration type 4ERP measured resistivity profile along the depth in chamber. Applying Archie's law, porosity profile was estimated with electrical resistivity. The tests result suggests that 4ERP can be new site investigation equipment with little disturbance.

• Transactions on Electrical and Electronic Materials
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• v.10 no.6
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• pp.203-207
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• 2009

We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of ITO thin films intended for use as anode contacts in OLED (organic light emitting diodes) devices. These ITO thin films are deposited by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar+$O_2$, and Ar+$H_2$) at $300{^{\circ}C}$. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon mixing gas has been changed from 0.5 sccm to 5 sccm and from 0.01 sccm to 0.25 sccm, respectively. The intensity of the (400) peak in the ITO thin films increased with increasing $O_2$, flow rate whilst the (400) peak was nearly invisible in an atmosphere of Ar+$H_2$. The electrical resistivity of the ITO thin films increased with increasing $O_2$ flow rate, whereas the electrical resistivity decreased sharply under an Ar+$H_2$ atmosphere and was nearly similar regardless of the $H_2$ flow rate. The change of electrical resistivity with changes in the ambient gas composition was mainly interpreted in terms of the charge carrier mobility rather than the charge carrier concentration. All the films showed an average transmittance of over 80% in the visible range. The OLED device was fabricated with different ITO substrates made with the configuration of ITO/$\alpha$-NPD/DPVB/$Alq_3$/LiF/Al in order to elucidate the performance of the ITO substrate. Current density and luminance of OLED devices with ITO thin films deposited in Ar+$H_2$ ambient gas is the highest among all the ITO thin films.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.576-579
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• 2008

Electrical impedance(EIT) for the multi-phase flow visualization is an imaging modality in which the resistivity distribution of the unknown object is estimated based on the known sets of injected currents and measured voltages on the surface of the object. In this paper, an EIT reconstruction algorithm based on the extended Kalman filter(EKF) is proposed. The EIT reconstruction problem is formulated as a dynamic model which is composed of the state equation and the observation equation, and the unknown resistivity distribution is estimated recursively with the aid of the EKF. To verify the reconstruction performance of the proposed algorithm, experiments with simulated multi-phase flow are performed.

• Korean Journal of Materials Research
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• v.11 no.11
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• pp.997-1000
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• 2001

Conducting perovskite oxide, $(Ba,Sr)RuO_3(BSR)$, which has many advantages for $(Ba,Sr)TiO_3(BST)$ due to their similarity in crystal structure, lattice constant and chemical composition, was prepared on n-type Si (100) by liquid delivery metalorganic chemical vapor deposition(LDMOCVD). The deposition characteristics of BSR were controlled by gas-phase mass-transfer in the experiment. The BSR films deposited at 50$0^{\circ}C$ and oxygen flow rate of 100 sccm(standard cc/min) showed an average roughness of 22 $\AA$and resistivity of 810 $\mu$$\Omega$-cm. The roughness of BSR films with oxygen flow rate showed a close relationship with the resistivity of films. BSR (110) peak shifted toward lower Bragg angle with increase of x in the$(Ba_x,Sr_{1-x})TiO_3$. The resistivity of BSR films increased from 810 to 924 $\mu$$\Omega$-cm with increase of Ba content(x).

• The Journal of Engineering Geology
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• v.21 no.2
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• pp.117-124
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• 2011

Soil deformations such as settlement, heaving and lateral flow have frequently happened on marine reclaimed soft grounds due to embankment filling or banking. The electrical resistivity survey was applied to investigate on ground surface such soil deformation without disturbance of ground. A test embankment was performed to assess soil deformation in marine reclaimed soft grounds, where was located at Sihwa area in western coast of Korean peninsula. The soft ground was composed of clayey sediments. After embankment filling, the boundary of soil deformation affected by the filling could be investigated with application of the electrical resistivity survey. The result of electric resistivity survey shows that the extent of deformation is about 5 m laterally to the southern direction of embankment and about 5~6 m vertically in depth, which is about 1-1.2 times of embankment height. This shows that the electric resistivity survey can be applied to interpret the ground deformation in a soft ground region.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.93-100
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• 2007

During tunnel excavation, drawdown of groundwater table or discharge from tunnel faces may not only reduce stability of tunnel and work efficiency but cause environmental problems. We have investigated the applicability of electrical resistivity survey for the establishment of the monitoring system for groundwater behavior and detecting flow channel of groundwater during tunnel excavation. The groundwater level was continuously measured at several points for 1 year. Survey was conduted at every 3 months using preinstalled electrical resistivity cables on site. The results show that observed changes in resistivity ratios in the area can be explained with observed changes in groundwater level. Thus, we believed that electrical resistivity analysed together with groundwater data can be applied for the monitoring of groundwater in tunnel area.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.7-11
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• 2019

We have investigated the effect of the hydrogen flow rate on the characteristics of IZO thin films for the TCO (transparent conducting oxide). For this purpose, IZO thin films are deposited by RF magnetron sputtering at 300℃ with various H₂ flow rate. To investigate the influences of the ambient gases, the flow rate of hydrogen in argon was varied from 0.1 sccm to 1 sccm. The IZO thin films deposited at 300℃ show crystalline structure having an (222) preferential orientation. The electrical resistivity of the crystalline-IZO films deposited at 300℃ and hydrogen gas of 0.8sccm was 3.192×10^-4Ω cm, the lowest value. As the hydrogen gas flow rate increased, the resistivity tended to decrease. The XPS profiles showed that the number of oxygen vacancy decreased as the hydrogen flow rate increased. The transmittance of the IZO films deposited at 300℃ were showed more than 80%.