• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.242-245
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• 2005

• Journal of Powder Materials
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• v.21 no.2
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• pp.114-118
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• 2014

In this study, an aluminum oxide layer for sealing treatment of nano-diamond powder was synthesized by anodizing under constant current. The produced pore size and oxide thickness were investigated using scanning electron microscopy. The pore size increased as the treatment time increased, current density increased, sulfuric acid concentration decreased, which is different from the results under constant voltage, due to a dissolution of the oxide layers. The oxide layer thickness by the anodizing increased as temperature, time, and current density increased. The results of this study can be applied to optimize the sealing treatment process of nano-diamond particles of 4-10 nm to enhance the resistances of corrosion and wear of the matrix.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.459-468
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• 2011

The main purpose of this study was to examine the influence of treatment amounts of Slurry Composting and Biofiltration liquid fertilizer (SCBLF) on biomass growth of Yellow poplar (Liriodendron tulipifera) and to compare bioethanol production from the harvested wood. Relative growth rate, biomass production and leaf characteristics were significantly enhanced by SCBLF treatment and medium treatment plot showed highest value. Nitrogen compounds and water content in SCBLF affected to increase chlorophyll contents which led improving biomass production (64.67%) and glucose contents (6.07%) than control. Organosolv and dilute acid pretreatments were preliminarily carried for bioethanol production, and the pretreatment processes were conducted at all the same solid to liquid ratio (1 : 10), reaction temperature ($150^{\circ}C$), preheating time (40 min) and residence time (10 min). The water insoluble solid recovery of Organosolv pretreatment with 1% sulfuric acid as a catalyst was the lowest and that of medium treatment plot was 44.81%. Exchangeable cations in SCBLF might be affected to increase pretreatment effect. The simultaneous saccharification and fermentation process was followed to determine the ethanol production of the pretreated biomass. The highest ethanol production yield based on initial weight was obtained from high treatment plotby Organosolv pretreatment with 1% sulfuric acid (16.11%). But regarding biomass production, medium treatment plot produced most, and bioethanol production was increased by 72.93% than control.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.1
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• pp.55-59
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• 1984

An organic compound fertilizer was manufactured using wet oxidation human waste as principal source of phosphorus and organic matter. The waste was treated with sulfuric and glutamic acids to increase the available and water-soluble $P_2O_5$ contents. The treatment of 0.1 N sulfuric acid with 24 hours curing was best way in recovering the maximum percentage of $P_2O_5$ originally in the waste. The particle size distribution of trial product varied considerably in the amount of glutamic acid used for granulation. The number of relatively large fertilizer particles was increased as the amount of glutamic acid was increased. The granule crushing strength was generally high in large granules in which 12.5 weight percent of glutamic acid were used for granulation. The trial product showed high moisture absorption due to its porous structure and chemical makeup.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.639-645
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• 2020

Among the components of redox flow battery (RFB), the electrode serves as a diffusion layer of an electrolyte and a path for electrons and also is a major component that directly affects the RFB performance. In this paper, chloric/sulfuric mixed acidwas used as a supporting electrolyte in RFB system with Fe2+/Fe3+ and V2+/V3+ as redox couple. The optimum electrode and activation temperature were suggested by comparing the capacity, coulombic efficiency and energy efficiency according to the electrode type and activation temperature. In the RFB single cell evaluation using 5 types of carbon electrodes used in the experiments, all of them showed close to the theoretical capacity to retain the reliability of the evaluation results. GFD4EA showed relatively excellent energy efficiency and charge/discharge capacity. In order to investigate the electrochemical performance according to the activation temperature, GFD4EA electrode was activated by heat treatment at different temperatures of 400, 450, 500, 600 and 700 ℃ under an air atmosphere. Changes in physical properties before and after the activation were observed using electrode mass retention, scanning electron microscope (SEM), XPS analysis, and electrochemical performance was compared by conducting RFB single evaluation using electrodes activated at each temperature given above.

• Fashion & Textile Research Journal
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• v.10 no.1
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• pp.101-105
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• 2008

This study was concerned with the influence of reaction conditions on the surface friction properties of Syrene-Butadiene Rubber(SBR) sheet when it was chlorinated by chemical treatment method using the sodium hypochlorite and sulfuric acid. The results of this study were as follows. SEM photographs of chlorinated SBR surface showed uneven etching caused by the chlorination. In the FTIR spectra, the intensity of C=C peak of SBR was decreased with increasing the concentration of sodium hypochlorite. Otherwise there was no trace of C=C peak in spectrum of SBR treated with 5 wt% NaOCl with pH 0.1 for 90 seconds. EDX spectra showed that relative content of chlorine of SBR was increased with increasing the amount of sodium hypochlorite, and also affected with pH condition of acid solution. Friction angle and friction coefficient of SBR were influenced with concentration of sodium hypochlorite, but were not with pH condition of acid solution.

• Carbon letters
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• v.7 no.4
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• pp.266-270
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• 2006

Multi-walled carbon nanotube-poly methyl methacrylate (MWNT/PMMA) nanocomposite has been prepared by in situ polymerization of MMA dispersed with MWNTs. The MWNTs were functionalized by nitric acid and sulfuric acid treatment, and this was confirmed by FTIR spectrometer. The solution mixture of MWNTs and MMA was partially polymerized at $80^{\circ}C$, followed by the addition of AIBN and polymerization at $50^{\circ}C$. The MWNT-PMMA composite was prepared by casting the pre-polymer on the glass plate, and the optical properties have been studied using UV-vis spectrometer. The acid treated MWNTs were well dispersed in MMA with fairly good dispersion stability, while flocculation and sedimentation was observed from raw MWNTs in MMA.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.4
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• pp.247-254
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• 1994

This study was conducted to characterize the chemical and mineralogical properties of representative phosphate rocks from North Carolina and Florida, and to find out the method for increasing the citric acid (two percent) solublility of phosphate rock. The the results are summerized as follows : 1. Major composition of phosphate rock was carbonate apatite containing small amounts of calcite and quartz. The differential thermal analysis(DTA) did not show endothermic or exothermic peak till $1,000^{\circ}C$. 2. Two percent citric acid solublility of phosphate rock was increased with the finess of particle size, but the water solublility was not affected by the particle size. Long time calcinated under high temperature had negative effect, while the incubation with 2% citric acid under low temperature had positive effect on solubility. 3. To increase the solubility of phosphate rock it was mixed with farmyard and barnyard manure and acidulated. Citrate solubility by treatment with sulfuric acid was more effective than nitric acid. Acidulation with thirty percent sulfuric acid increased both citric acid solubility and water solublility. Treatment with glutamic acid had little effect on the solubility of phosphate rock.

• Corrosion Science and Technology
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• v.6 no.3
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• pp.140-146
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• 2007

In the paper, with corrosion velocity measurement and metallographic observation on specimens after sulfuric acid/ferric sulfate boiling experiment, intergranular corrosion tendency of the new type ultra low carbon stainless steel developed by ourselves which experienced solution treatment at different temperatures was evaluated. A VHX 500 super depth field tridimensional microscope was used to observe corrosion patterns on the sample surfaces. The depth and width of grain boundary corrosion groove were measured by the tridimensional microscope, which indicated that the corrosion degrees of the samples which received solution treatment at different temperatures are quite different. Transgranular corrosion at different degree occurred along with forged glide lines. After comparison it was proved that the stainless steel treated at $1100^{\circ}C$ performs very well against intergranular corrosion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.248-253
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• 1990

Germination and seedling growth of chinese milkyetch (Astragalus sinicus L. Line A) seeds were measured at four temperatures (15. 25. 30, and 35$^{\circ}C$), three polyethylene glycol (PEG) 10.000 (MW) solutions (0, 20 and 25 g/100$m\ell$ H$_2$O), and five sulfuric acid treatments (conc, H$_2$SO$_4$: Seeds/weight base: 0, 1:1 10min.. 1:1 20min.. 1:1.5 10min. and 1:1.5 20min, immersion), Adjustments of PEG 10.000 solutions were based on water potentials of 0.0, -0,5 and -0.8 ㎫ at room temperature. Observations were taken at 7 days for each treatment combinations. Germination percent of chinese mikvetch seeds was the highest at 15$^{\circ}C$ and seeding length was the longest at 25$^{\circ}C$. Both germination percent and seedling length were rapidly decreased as PEG concentration increased from 0 to 25g/100$m\ell$ H$_2$O. The highest germination percent was found at PEG 20 and 25 of 15$^{\circ}C$ among those of four temperatures, Sulfuric acid treatments showed little effect on germination percent and seedling length compared to untreated control, However. in the case of PEG 0, greater germination perccent was obtained at the treatment of 1:1.5 for 10 minutes immersion, The result of this study-indicated that germination of chinese milkvetch seeds was affected mostly by moisture stress conditions.