• 한국산업융합학회 논문집
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• 제20권4호
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• pp.257-263
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• 2017

The following thesis researched into the characteristics of electrolytic ion water with different levels of electrical conductivity by adding NaCl into tap water which is for experimental use in multi-layered electrolytic ion water generator. Electrolytic ion water is generated by underwater electrolysis and the electrolysis generator has a simple structure, is easy to control and is highly utilized in industries. Electrolytic ion water is useful in many areas since it has a superior sterilizing power, has no possibility of secondary pollution itself as water and removes active oxygen. In the experiment, we used tap water with NaCl excluded and water with three different levels of electrical conductivity by changing NaCl concentration levels into three levels. The features of current and voltage in electrolytic ion water represented a form of quadric instead of the linear characteristic following ohm's law. As well, as the electric conductivity of water and applied voltage increased, we were able to generate much stronger acid water and alkali water.

• Advances in materials Research
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• 제6권1호
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• pp.79-91
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• 2017

In the present work, a design of experiment (DOE) technique using Taguchi method, has been applied to optimize the properties of ODS tungsten heavy alloys(WHAs). In this work Taguchi method involves nine experiments groups for four processing parameters (compaction pressure, sintering temperature, binding material type, and oxide type) with three levels was implemented. The signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were employed to obtain the optimal process parameter levels and to analyze the effect of these parameters on density, electrical conductivity, hardness and compressive strength values. The results showed that all the chosen factors have significant effects on all properties of ODS tungsten heavy alloys samples. The density, electrical conductivity and hardness increases with the increase in sintering temperature. The analysis of the verification experiments for the physical properties (density and Electrical conductivity) has shown that Taguchi parameter design can successfully verify the optimal parameters, where the difference between the predicted and the verified values of relative density and electrical conductivity is about 1.01% and 1.15% respectively.

• 동력기계공학회지
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• 제21권5호
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• pp.71-78
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• 2017

The purpose of this study is to propose the basic data for the development of a sensor capable of simultaneously measuring the liquid-level, concentration and temperature of a urea tank using ultrasonic and electrical conductivity sensors for diesel vehicles with a urea-SCR system. It was found that the liquid-level of the urea tank using the ultrasonic sensor showed a good linearity with the actual liquid-level, and the urea concentration maintained good linearity in the range of 32.5 wt% to 10 wt%. It was an effective measurement of urea concentration to use the electrical conductivity sensor in the temperature range of $-10{\sim}22^{\circ}C$ and to use the ultrasonic sensor at $22^{\circ}C$ or more. Simultaneous measurement of concentration, liquid-level and temperature of the urea tank will be possible by attaching the electrical conductivity sensor and the ultrasonic sensor (split-type) to one sensor together.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.324-324
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• 2006

Nb and Ti were added to 316 stainless steel, and then heat-treatments and surface treatments were performed on the 316 stainless steel and the Nb- and Ti-added alloys. All samples indicated enhanced electrical conductivity after surface treatments, whereas they showed low electrical conductivity before surface treatments due to the existence of non-conductive passive film on the alloy surface. In particular, the Hb- and Ti-added alloys showed remarkable enhancement of electrical conductivity compared to the original alloy, 316 stainless steel. Surface characterization revealed that small carbide particles formed on the alloy surface after surface treatments, while the alloys indicated flat surface structure before surface treatments. $Cr_{23}C_6$ mainly formed on the 316 stainless steel, and NbC and TiC mainly formed on the Nb- and Ti-added alloys, respectively. We attribute the enhanced electrical conductivity after surface treatments to the formation of these carbide particles, possibly acting as a means of electro-conductive channel through the passive film. Furthermore, NbC and TiC are supposed to be more effective carbides than $Cr_{23}C_6$ as electro-conductive channels of stainless steel

• 한국재료학회지
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• 제12권6호
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• pp.436-441
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• 2002

Effect of Sn addition on the stress corrosion cracking(SCC) resistance of the Al-Cu-Mn cast alley was investigated by C-ring teat and electrical conductivity measurement, The electrical conductivity and SCC resistance increased by Sn addition. The alley containing 0,10%Sn showed maximum electrical conductivity and the best SCC resistance. At the same composition, the electrical conductivity and SCC resistance increased from peak aged condition to ever aged condition. The PFZ and coarse precipitates along the grain boundary were observed from TEM micrographs. The fracture mode of the alloy was confirmed as intergranular type and showed brittle fracture surface. The SCC mechanism of the alloy was concluded as the anodic dissolution model, The maximum hardness was increased from 130Hv in the Sn-free alloy to 156Hv in the 0.10%Sn added alloy.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.261-264
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• 2000

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li polymer battery. This paper describes temperature dependence of conductivity, impedance spectroscopy, electrochemical properties of PAN/PVDF electrolytes as a function of a mixed ratio. PAN/PVDF based polymer electrolyte films were prepared by thermal gellification method of preweighed PAN/PVDF, plasticizer and Li salt. By adding PVDF and as a function of plasticizer mixed ratio to PAN-LiClO4 electrolyte, its conductivity was higher than that of PAN-$LiClO4_4$ electrolyte. The conductivity of PAN/PVDF electrolytes was $10^{-3}S/cm$. $10PAN10PVDFLiClO_4PC_5EC_5$ electrolyte shows the better conductivity of the others. Steady state current method and ac impedance used for the determination of transference numbers in PAN/PVDF electrolyte film. The transference number of $10PAN10PVDFLiClO_4PC_5EC_5$ electrolyte is 0.45.

• 한국환경복원기술학회지
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• 제5권2호
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• pp.17-24
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• 2002

This research was conducted to investigate the influences caused by solifluction soil on the physicochemistry of stream water quality at the riparian area four points in the northeastern part of the Bughansan National Park from March to May of 2001. The average pH of stream water was higher than those in the caused by solifluction soil. The average electrical conductivity of upstream water was about 0.8~1.7 times lower than those in the caused by solifluction soil, but the average electrical conductivity of downstream water was about 1.6~3.8 times higher than those in the caused by solifluction soil. Therefore, these results showed that the water quality of downstream was worse than that of upstream. Twelve factors including the physicochemistry on the stream water and caused by solifluction soil were analyzed by spss/pc+ for the data collected from during March to May of 2001. pH of stream water was very significantly correlated with pH and electrical conductivity at the caused by solifluction soil. And the electrical conductivity of stream water was very significantly correlated with electrical conductivity and the amount of cation($Na^+$, ${NH_4}^+$, $Mg^{2+}$) at the caused by solifluction soil.

• 한국재료학회지
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• 제20권5호
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• pp.271-277
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• 2010

In this paper two aspects of the percolation and conductivity of carbon black-filled polyethylene matrix composites will be discussed. Firstly, the percolation behavior, the critical exponent of conductivity of these composites, are discussed based on studying the whole change of resistivity, the relationship between frequency and relative permittivity or ac conductivity. There are two transitions of resistivity for carbon black filling. Below the first transition, resistivity shows an ohmic behavior and its value is almost the same as that of the matrix. Between the first and second transition, the change in resistivity is very sharp, and a non-ohmic electric field dependence of current has been observed. Secondly, the electrical conduction property of the carbon black-filled polyethylene matrix composites below the percolation threshold is discussed with the hopping conduction model. This study investigates the electrical conduction property of the composites below the percolation threshold based on the frequency dependence of conductivity in the range of 20 Hz to 1 MHz. There are two components for the observed ac loss current. One is independent of frequency that becomes prevalent in low frequencies just below the percolation threshold and under a high electrical field. The other is proportional to the frequency of the applied ac voltage in high frequencies and its origin is not clear. These results support the conclusion that the electrical conduction mechanism below the percolation threshold is tunneling.

• 한국농공학회지
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• 제43권4호
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• pp.37-49
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• 2001

This study was performed in order to produce the basic data for developing prediction techniques of desalinization to be applicable to reclaimed tidal lands at the beginning stage. the desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage. The 5 soil samples used in this study were collected in 4 tidal land reclamation projects. Regression equations were obtained in order to investigate the changes of electrical conductivity during the desalinization of reclaimed tidal lands and to estimate water requirements for desalinization. The results obtained from this study were summarized as follows: 1. According to USDA Salinity Laboratory classification system of salt affected soils the reclaimed tidal land soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. With the increase of the water requirements for desalinization the electrical conductivity was decreased with high degree of correlationships and the desalinization effects were remakable in both the leaching method and the rinsing method. 3. In case of the leaching method the electrical conductivity had been reduced below the classification value of salt affected soils when the depth o water leached per unit depth of soil (Dwl/Ds) was 0.3 and the desalinization effects showed a tendency to be much the same in each treatment.

• 한국재료학회지
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• 제27권3호
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• pp.155-160
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• 2017

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.