• Asian Journal of Turfgrass Science
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• v.5 no.1
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• pp.1-10
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• 1991

The purpose of the experiment was to determine the effect of nitrogen sources (urea, ammonium sulphate, ammonium nitrate) and potassium sources (potassium chloride, potassium sulphate) on the growth and quality of Zoysia japonica Steud. This experiment was conducted at Seoul City University turf field from 1988 to 1989. The results of this experiment were summarized as follows; 1. Urea and Ammonium sulphate resulted in superior clipping yield compared to ammonium nitrate. The growth of rhizome and stolon increased significantly with urea forms, but ammonium sulphate treated plots exhibited the highest the growth rate of root. 2. Ammonium sulphate showed best turf color rating while ammonium nitrate resulted in the poorest. Prolongation of the green period showed longer in ammonium sulphate and urea treated plots than ammoium nitrate. 3. Urea and ammonium sulphate exhibited superior visible quality and shoot density compared to ammonium nitrate. 4. The uptake of mineral nutrient showed the highest concentration with urea plots. Surface soil pH was allowed to become slightly acid with the ammonium sulphate and potassium sulphate treatments, while the application of N and K sources did not cause significant differences in mineral element content in soil.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.283-286
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• 1999

Transparent conductive aluminum-doped ZnO(AZO) films Were prepared by a ultrasonic spray pyrolysis method at the substrate temperature below 23$0^{\circ}C$. A vertical type hot wall furnace was used as a reactor in the deposition system. Zinc acetate dissolved in methanol was selected as a precursor. The substrate temperature was varied from 18$0^{\circ}C$to 24$0^{\circ}C$. Aluminum (Al) was doped into ZnO films by incorporating anhydrous aluminum chloride (AlCl$_3$) in the zinc acetate solution. The proportion of the Al in the starting solution was varied from 0 wt % to 3.0 wt %. The crystallographic properties and surface morphologies of the films were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The resistivity of the films was measured by the Van der Pauw method, and the mobility and carrier concentration were obtained through the Hall effect measurements Transmittance was measured in the visible region. The effects of substrate temperature and aluminum content in the starling solution on the structural and electrical properties of the AZO films are discussed

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.3
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• pp.287-297
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• 1994

The purpose of this study is to investigate the Improvement of fiber surface, tenacity & elogation, fabric counts, thickness, handle, moisture regain, static voltage, handle, dyeability when polyester fabrics are treated with NaOH solution adding quartemary ammonium salt (Benzyl dimetyl dodecyl ammonium chloride . BDMDAC) The results are as follows. I. In regard to the method of processing VET, when the PET fabrics are alkaline-hydrolyzed adding BDMDAC, the weight loss of PET fabrics increased remarkably to the increse of BDMDAC concentration than when they are treated only in NaOH solution. When PET fabrics are alkaline-hydrolyzed the amount of BDMDAC as the catalyst is proper lg/1 II. The change in physical & chemical properties of alkaline-hydrolyzed PET fabrirs. 1. As the amount of the weight loss on PET fabrics increased, the void space of the PET yale increased but tenacity & elongation and thickness decreased. 2. The fabric counts of PET increased due to shrinkage by alkaline-hydrolydzing. 3. As the amount of of the weight loss on PET fabrics increased. NUMERI, FUKURAMI, increaseed and KOSHI decreased and Total hand value(T.H.V) in all cases increaseed. When the weight Ioss is 30.9% T.H.V. is best. 4. Moisture regain of PET fabrics a little increased by alkaline-hydrolyzing treatment. As the weight loss increased, static voltage is decreased. 5. The last dye absorption is different according to the degree of the Affinity. In regard to the difference of dye color, the dyestuff of low molecular weight dyed for deep color.

• Corrosion Science and Technology
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• v.17 no.4
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• pp.176-182
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• 2018

Corrosion of the Cu alloy with 10wt% Ni in stagnant seawater with residual free chlorine was investigated. Despite that fact that Cu alloys are widely used for seawater applications due to their stubborn resistance to chloride attack, not much is known as to how the residual free chlorine in seawater affects corrosion of Cu and its alloys. In this work, immersion tests were conducted in the presence of different levels of chlorine for 90-10 Cu-Ni samples, one of the most frequently used Cu alloys for seawater application, mostly in shipbuilding. The results revealed no evidence for accelerated corrosion of the Cu-Ni alloy even in the presence of 5 ppm residual chlorine in seawater, signifying that the Cu-Ni alloy can be more tolerant to residual chlorine that has been commonly cited by the shipbuilding industry. However, comparison of polarization behavior of the alloy samples in the presence of different electrolytes with different concentrations of residual chlorine suggests that higher concentration of chlorine could increase the corrosion rate of the Cu-Ni alloy. Furthermore, it is suggested that microorganisms in the seawater could increase the corrosion rate of the Cu-Ni alloy by encouraging exfoliation of the corrosion product off the metal surface.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.965-971
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• 2001

To estimate the reliability of 12Cr alloy steel, the material of turbine blade in the steam power plant, Its corrosion susceptibility and fatigue characteristics in NaCl and Na$_2$SO$_4$solution with the difference of concentration and temperature was investigated. The polarization tests recommended in ASTM G5 standard for corrosion susceptibility in the various corrosive solutions was estimated. It showed that the higher temperature, the faster corrosion rates and corrosion rates were the fastest in 3.5 wt.% NaCl and 1M Na$_2$SO$_4$solution. From these results, the degradation conditions were determined in distilled water, 3.5 wt.% NaCl and 1M Na$_2$SO$_4$solution at room temperature, 60$\^{C}$ and 90$\^{C}$ during 3, 6 and 9 months. Its surface had a few pits for long duration. But, it was not susceptible in sulfide and chloride condition of several temperatures. If the degraded 12Cr alloy steel and non-degraded one were compared with fatigue characteristics, Any differences were not found regardless of temperature and degradation period.

• Membrane and Water Treatment
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• v.8 no.4
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• pp.323-336
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• 2017

The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute permeation was carried out under applied pressure of 5 bar at $25^{\circ}C$. Surface properties of TFC membrane were characterized by ATR-FTIR, SEM and AFM. The performance test indicated that 3.5 wt% of MPD, 0.35 wt% of TMC and curing temperature of $75^{\circ}C$ are the optimum conditions. Moreover, the permeate flux was $4.3{\frac{L}{m^2\;h}}$ and acetic acid rejection was about 43% at these conditions.

• Journal of Electrochemical Science and Technology
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• v.10 no.1
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• pp.61-68
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• 2019

Well aligned $SnO_2$-doped ZnO nanorods were prepared by single step or 2-step electrochemical depositions in a mixture solution of zinc nitrate hexahydrate, ammonium hydroxide solution and 0.1 M tin chloride pentahydrate. The morphologies of electrochemically deposited $SnO_2$-doped ZnO were transformed from plain (or network) structures at low reduction potential to needles on hills at high reduction potential. Well aligned ZnO was prepared at intermediate potential ranges. Reduction reagent and a high concentration of Zn precursor were required to fabricate $SnO_2$ doped ZnO nanorods. When compared to results obtained by single step electrochemical deposition, 2-step electrochemical deposition produced a much higher density of nanorods, which was ascribed to less potential being required for nucleation of nanorods by the second-step electrochemical deposition because the surface was activated in the first-step. Mechanisms of $SnO_2$ doped ZnO nanorods prepared at single step or 2-step was described in terms of applied potential ranges and mass-/charge- limited transfer.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.549-562
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• 2020

Deionized water, methanol, and ethanol were investigated for their effectiveness at dissolving LiCl-KCl-UCl3 at 25, 35, and 50℃ using inductively coupled plasma mass spectrometry (ICP-MS) to study the concentration evolution of uranium and mass ratio evolutions of lithium and potassium in these solvents. A visualization experiment of the dissolution of the ternary salt in solvents was performed at 25℃ for 2 min to gain further understanding of the reactions. Aforementioned solvents were evaluated for their performance on removing the adhered ternary salt from uranium dendrites that were electrochemically separated in a molten LiCl-KCl-UCl3 electrolyte (500℃) using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). Findings indicate that deionized water is best suited for dissolving the ternary salt and removing adhered salt from electrodeposits. The maximum uranium concentrations detected in deionized water, methanol, and ethanol for the different temperature conditions were 8.33, 5.67, 2.79 μg·L-1 for 25℃, 10.62, 5.73, 2.50 μg·L-1 for 35℃, and 11.55, 6.75, and 4.73 μg·L-1 for 50℃. ICP-MS analysis indicates that ethanol did not take up any KCl during dissolutions investigated. SEM-EDS analysis of ethanol washed uranium dendrites confirmed that KCl was still adhered to the surface. Saturation criteria is also proposed and utilized to approximate the state of saturation of the solvents used in the dissolution trials.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4474-4480
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• 2022

Deep geological disposal using a multibarrier system is a promising solution for treating high-level radioactive (HLRW) waste. The HLRW canister represents the first barrier for the migration of radionuclides into the biosphere, therefore, the corrosion behavior of canister materials is of significance. In this study, the electrochemical behaviors of SS316L, Ti-Gr.2, Alloy 22, and Cu in naturally aerated KAERI underground research tunnel (KURT) groundwater solutions were examined. The corrosion potential, current, and impedance spectra of the test materials were recorded using electrochemical methods. According to polarization and impedance measurements, Cu exhibits relatively higher corrosion rates and a lower corrosion resistance ability than those exhibited by the other materials in the given groundwater condition. In the anodic dissolution tests, SS316L exposed to the groundwater solution exhibited the most uniform corrosion, as indicated by its surface roughness. This phenomenon could be attributed to the extremely low concentration of chloride ions in KURT groundwater.

• Membrane and Water Treatment
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• v.13 no.2
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• pp.105-110
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• 2022

Al₂O₃ positively charged nanofiltration composite membrane was successfully prepared with aluminate coupling agent (ACA) as modifier, sodium bisulfite (NaHSO₃) and potassium persulfate (K₂S₂O₈) as initiator and methacryloyloxyethyl trimethylammonium chloride (DMC) as crosslinking monomer. The surface of the membrane before grafting and after polymerization were characterized by SEM and FT-IR. Three factor and three-level orthogonal experiments were designed to explore the optimal conditions for membrane preparation, and the optimal group was successfully prepared. The filtration experiments of different salt solutions were carried out, and the retention molecular weight was determined by polyethylene glycol (PEG). The results showed that the polymerization temperature had the greatest effect on the rejection rate, followed by the reaction time, and the concentration of DMC had the least effect on the rejection rate. The rejection rates of CaCl₂, MgSO₄, NaCl and Na₂SO₄ in the optimal group were 83.8%, 81.3%, 28.1% and 23.6% (average value), respectively. The molecule weight cut-off of 90% (MWCO) of the optimal group was about 460, which belongs to nanofiltration membrane.