• Corrosion Science and Technology
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• v.16 no.5
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• pp.227-234
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• 2017

Reference electrodes are generally implemented for the purpose of monitoring the cathodic protection potentials of buried or immersed metallic structures. In the market, many types of reference electrodes are available for this purpose, such as saturated calomel, silver/silver chloride and copper/copper sulfate. These electrodes contain a porous ceramic junction plate situated in the cylindrical body bottom to permit ionic flux between the internal electrolyte (of the reference electrode) and the external electrolyte. In this work, the copper/copper sulfate reference electrode was modified by replacing the porous ceramic junction plate for a metallic platinum wire. The main purpose of this modification was to avoid the ion copper transport from coming from the inner reference electrode solution into the surrounding electrolyte, and to mitigate the copper plating on the coupon surfaces. Lab tests were performed in order to compare the performance of the two mentioned reference electrodes. We verified that the experimental errors associated with the measurements conducted with developed reference electrode would be negligible, as the platinum surface area exposed to the surrounding electrolyte and/or to the reference electrolyte are maintained as small as possible.

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.477-484
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• 1994

The yttria stabilized zirconia(YSZ) thin films for solid oxide fuel cell (SOFC) were fabricated by an electrochemical vapor deposition(EVD) technique using YCl3+ZrCl4+H2O gas system. The YSZ films were deposited under reduced pressure at the temperature of 1000~120$0^{\circ}C$ on the porous alumina substrates. The deposition rate, chemical composition and growth morphology were investigated by SEM, XRD, EDS. The growth rates of the films obeyed a parabolic rate law, representing that the growing process is controlled by an electrochemical transport through the YSZ film. The Y2O3 content of the films was about 10 mol%, equal to the composition of metal chloride reactant gases, approximately. The YSZ films were highly dense, the growing features showed columnar structure and surface morphologies were changed with the EVD conditions.

• Journal of the Korean institute of surface engineering
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• v.28 no.4
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• pp.199-206
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• 1995

A kinetic study on the electrodeposition of Ni-Zn-P ternary alloys onto a steel in chloride solutions was carried out using a rotating disc electrode. The coatings were characterized using SEM/EPMA and A. A. analysis. The results showed that the plating rates of three components were increased with applied potential, disc rotating speed and temperature. The activation energies of Ni, Zn and P of the coatings were 6.1, 5.1 and 8.0 kcal/mole respectively. Therefore, the deposition rates were controlled partly by surface electrochemical reaction and partly by mass transport. As the potential, temperature of bath and rotating speed of cathode disc were raised, the vol. % ratios of Ni and P of coating layer were increased but that of Zn decreased. The effect of coating parameters on the surface morphology was also examined.

• Polymer(Korea)
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• v.39 no.2
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• pp.268-274
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• 2015

In this paper, the isothermal crystallization kinetics of a functional PP (FPP) with different grafting yields (GY)-methacryloxyethyltrimethyl ammonium chloride (DMC) grafted PP were investigated by differential scanning calorimetry (DSC). The results showed that the crystallization rate of FPP (GY=4.83%) was the highest for all of the studied samples. Furthermore, for the FPP with different GY, the value of $t_{1/2}$ became longer with increasing the grafting yield (GY). The possible explanation was that the quaternary ammonium groups introduced affected the crystallization process of the FPP in two opposite directions, i.e. promoting the nucleation and hindering the transport of the chain molecules towards the growing nuclei. Polarized optical micrographs showed that the DMC chains acted as nucleating agents, which accelerated the nucleation. In addition, the results showed the FPP had lower nucleation free energy than the PP. This study would be useful for designing the processing parameters of the grafted samples.

• Computers and Concrete
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• v.23 no.2
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• pp.107-119
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• 2019

In-service reinforced concrete structures are simultaneously subjected to a combination of multi-deterioration environmental actions and mechanical loads. The combination of two or more deteriorative actions in environments can potentially accelerate the degradation and aging of concrete materials and structures. This paper reviews the coupling and synergistic mechanisms among various deteriorative driving forces (e.g. chloride salts- and carbonation-induced reinforcement corrosion, cyclic freeze-thaw action, alkali-silica reaction, and sulfate attack). In addition, the effects of mechanical loads on detrimental environmental factors are discussed, focusing on the transport properties and damage evolution in concrete. Recommendations for advancing current testing methods and predictive modeling on assessing the long-term durability of concrete with consideration of the coupling effects are provided.

• Nuclear Engineering and Technology
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• v.50 no.7
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• pp.1148-1153
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• 2018

The Leaking Fuel Experiment test facility was designed to simulate the activity release from spent leaking fuel rods under steady state and transient conditions in the spent fuel pool. The experimental rig included an electrically heated fuel rod with different defects and a cooling system. The fission product transport was simulated by potassium-chloride. The conductivity changes of the water in the cooling system were measured to provide information about the amount of released solution. Defects of different sizes and positions were applied, together with a wide range of rod powers to simulate decay heat. The produced data can be used for predicting the activity release from leaking fuel under storage conditions and for the interpretation of fuel examination procedures.

• Membrane Journal
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• v.25 no.5
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• pp.398-405
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• 2015

Facilitated transport is considered to be a possible solution to simultaneously improve permeability and selectivity, which is challenging in normal polymeric membranes based on solution-diffusion transport only. We investigated the effect of adding mesoporous $TiO_2$ ($m-TiO_2$) upon the separation performance of facilitated olefin transport membranes comprising poly(vinyl pyrrolidone), Ag nanoparticles, and 7,7,8,8-tetracyanoquinodimethane as the polymer matrix, olefin carrier, and electron acceptor, respectively. In particular, $m-TiO_2$ was prepared by means of a facile, mass-producible method using poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymer as the template. The crystal phase of $m-TiO_2$ consisted of an anatase/rutile mixture, of crystallite size approximately 16 nm as determined by X-ray diffraction. The introduction of $m-TiO_2$ increased the membrane diffusivity, thereby increasing the mixed-gas permeance from 1.6 to 16.0 GPU ($1GPU=10^{-6}cm^3$(STP)/($s{\times}cm^2{\times}cmHg$), and slightly decreased the propylene/propane selectivity from 45 to 37. However, both the mixed-gas permeance and selectivity of the membrane containing $m-TiO_2$ rapidly decreased over time, whereas the membrane without $m-TiO_2$ had more stable long-term performance. This difference might be attributed to specific chemical interactions between $TiO_2$ and Ag nanoparticles, causing Ag to lose activity as an olefin carrier.

• The Journal of Internal Korean Medicine
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• v.22 no.1
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• pp.29-38
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• 2001

When I evaluated the component variation of Naesowhajung-tang by the three types of extraction method, and each type's effects on the gastrointestinal tract, I got the following results. 1. The output ratio of extracts made out of Naesowhajung-tang were not significantly different among 13.8% of water extract(Sample-I), 13.5% of 50% ethanol extract(Sample-II), and 15.6% of water extract by spray dryer(Sample-III). 2. magnolol, honokiol, hesperidin, naringin, poncirin and glycyrrhizin Sample II had the largest amount of the following contents: magnolol, honokiol, hesperidin, naringin, poncirin and glycyrrhizin. 3. All the extracts of Naesowhajung-tang showed the inhibitory effect on the smooth muscle contraction of the isolated ileum in mice and fundus-strip in rats induced by acetylcholine chloride and barium chloride. 4. High concentration Sample-II was recognized to be effective in preventing gastric ulcers in Shay's rats. but not in the other rat group. 5. All the extracts of Naesowhajung-tang were recognized to be effective in preventing gastric ulcers induced by Ethanol-HCl in rats. 6. The increase of transport ability in the small intestine was recognized only when the concentration of all the samples was doubled, but not in the other concentrations. 7. The increase of transport ability in the large intestine was recognized only when the concentration of Sample-II was doubled, but not in other concentration. Using the results mentioned above, I suggest that Sample-II has more significant effects on the gastrointestinal tract than the others.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.342-347
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• 1998

Light-weight conductive polymer composites were prepared by incorporating polyheterocycles such as polypyrrole and polythiophene into pores of a highly porous cross-linked polystyrene, host polymer, to form a conductive network. The highly hydrophobic and porous host polymer was synthesized by concentrated emulsion polymerization method. Polypyrrole-based composites, prepared by employing ferric chloride-methanol system, showed a conductivity as high as 0.82 S/cm. Conductivity of polythiophene-based composites, prepared from ferric chloride-acetonitrile system, was 6.05 S/cm. Conductivity of compositivity was influenced by the initial molar ratio of oxidant to monomer as well. SEM micrographs of the composites showed that conducting polymer coated uniformly the inside wall of the porous host polymer. Shielding effectiveness of the polypyrrole-based composites and of the polythiophene-based composites were 15.2 dB and 22.5 dB at 2.0 GHz, respectively. In the temperature range from 20 to 300K, a polypyrrole impregnated composite exhibited seimiconducting behavior and followed the variable range hopping(VRH) model for charge transport.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.5
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• pp.155-163
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• 2004

The objectives of this study were to characterize the wastewater flow through the VFS, and relate this to the P removal in the VFS. A total of 68 subsurface wells (20∼40 cm below the soil surface) and 35 surface wells (0~5 cm), and the application of chloride tracer were used to investigate flow paths and soluble reactive P (SRP) removal from the 21 m wide and 33 m long VFS receiving dairy milkhouse waste. The early chloride breakthroughs in wells in the center of the VFS showed that the milkhouse waste flows preferentially down in the center of the hillslope. The locally saturated area created near the discharge pipe in the center of the VFS accelerates surface flow that contributed to rapid transport of P to the down slope area. Although VFS of 33m long eventually reduced SRP to lower than 0.2 mg/L in most cases, SRP is less effectively removed in the areas where soil saturation occurred. It is suggested that the effort to distribute the wastewater uniformly to avoid soil saturation and reduce the flow velocity need to be considered in new designs.