• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1204-1208
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• 1996

The organic impurities are formed in the p-xylene oxidation process to terephthalic acid(TPA) and they are present in the filtrate(mother liquor) solution or the TPA particles. The organic impurities present in the p-xylene oxidation are formed through side reactions or incomplete reaction. In this study, the main organic impurities, such as benzoic acid, p-toluic acid, p-tolualdehyde, 4-carboxybenzaldehyde, phthalic acid, isophthalic acid, trimellitic acid, and 4-hydroxymethyl benzoic acid were identified simultaneously by gas chromatograghy. The above impurities were reacted with bis(trimethylsilyl)trifluoroacetamide in the mixture of internal standard solution and pyridine solution by trimethylsilylation, where the internal standard solution was made by 99% bis (trimethylsilyl)trifluoroacetamide and 1% trimethylchlorosilane. The main organic impurities above mentioned can be analyzed quantitatively within 50 min.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2079-2091
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• 2024

In this paper, a model is developed for calculating pH in the presence of organic impurities due to dissolution of paint and/or continuous injection of organic impurities in the sump. The model is implemented in the AnCheBi code for the analysis of chemical behaviors of the iodine in the containment when the pH changes during a severe accident. Validation of the model is performed with P10T2 and P11T1 experiments carried out by AECL in Canada under the BIP project. Importance analyses of the pH calculation model in the AnCheBi code are then performed with the aforementioned experimental data via Latin hypercube sampling on the reaction coefficients, sensitivity analyses of AnCheBi, and calculation of the correlation coefficients between the reaction coefficients and figure of merits (the pH and the concentrations of the various iodine species). From the importance analyses, we provide the sensitivity of the pH calculation model to the change of pH and the concentrations of the various iodine species and the reaction coefficients related with the dominant phenomena underlying the change of pH and the concentrations of the species.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3275-3279
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• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• Resources Recycling
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• v.29 no.6
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• pp.57-64
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• 2020

In this study, removal of OCA and organic impurities for recycling LCD touch panel glass was conducted by mechanical and chemical dissolution methode. Cut mill and oscillation mill were used for mechanical crushing of touch panel, and water, ethanol, dichloromethane were used to remove OCA and organic impurities. As a result of TGA, when applied only dicloromethane in the process, the efficiency of organic removal was to be best. In addition, removal effect of organic impurities increased as the cleaning temperature increased. As a result of zeta potential analysis to confirm the dispersion degree of touch panel glass in the solvent, the absolute value of the zeta potenial of water with the lowest cleaning effect was lower than other solvents, and it was confirmed that efficiency of organic removal is affected not only by the chemical dissolution properties but also the physical dispersion properties in the solvent.

• Transactions on Electrical and Electronic Materials
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• v.13 no.2
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• pp.89-92
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• 2012

The effect of organic impurities on the electrical properties of a neat epoxy resin was studied. 0.05, 0.5 and 1.0 phr of iso-propyl alcohol (IPA) and methylene chloride (MC) mixture (50/50 wt%) were used as impurities. The current density, volume resistance and impedance characteristics of the epoxy/IPA/MC systems were measured with a high voltage source meter and broadband dielectric spectroscopy. Glass transition temperature (Tg) was measured by a differential scanning calorimetry (DSC) and it was found that Tg decreased slightly with increasing IPA/MC content. It was also found that Tg values of the epoxy systems with various IPA/MC contents were closely related to the current density, volume resistance and impedance characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.206-206
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• 2007

The nano-technology becomes a key technology in every field and it wasn't specialized any more. But nano-technology didn't applied every fields actively. Because It is difficult to fabricate the nanocomposites using nano-partie without aggregation of nano-size particles. So many researcher used organic solvent for dispersion in polymer nanocomposites. But organic solvent affected the electrical, mechanical, and thermal properties in the sample. We aimed this point that investigated the effect of organic solvent in the sample by evaporated temperature(60, 80, $100^{\circ}C$). In results, nano-particles affected to electrical properties of the sample due to decrease the energy gap. And at 120 Hz, impedance value of samples by varied evaporated temperature was decreased only at $60^{\circ}C$ dramatically. It's means that organic solvent role to impurities and decreased the activation energy. And these impurities contributed to the conductivity in the sample.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.49-58
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• 2013

A selected halogenated organic contaminant, monochlorophenol was successfully degraded by photocatalytic reaction in a circulating batch system. The photocatalytic degradation in most cases follows first-order kinetics. The photocatalytic reaction rate increased in the $TiO_2$ dosage range of 0.1 g/L to 0.4 g/L, then decreased with further increase of the dosage. Also the degradation rate increased over the range of the retention time from 0.49 min. to 0.94 min., then decreased with further increase of the retention time in the circulating batch reactor. The photocatalytic activity was enhanced by addition of metal impurities, platinum(Pt) and palladium(Pd) onto the photocatalysts. The photocatalytic degradation rate increased with the increase of Pt and Pd in the content range of 0 to 2wt %, then decreased with further increase of the metal contents. Therefore the metal loading to $TiO_2$ influence the degradation rate of a halogenated organic compound by acting as electron traps, consequently reducing the electron/positive hole pair recombination rate.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.233-240
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• 1999

Industrial waste which highly loaded by halogenide phenols was photooxidized by laboratory-scale photooxidation of these organic impurities in the presence of aerotropic and titaniumdioxide as photocatalyst. The disapperance of organic compounds was determined as a function of the irradiation time. Some contaminants such as 2-chlorophenol, 2-bromphenol, 3-bromphenol, 4-bromphenol, 2,4-dibromophenol and 2,6-dibromophenol were photodegraded separately to obtain information on the reaction rates, reactivities, and reaction mechanisms of the photooxidation, and on the stoichiometric correlation between organic reactant and inorganic products concentration in the course of the photocatalytic photoreaction.

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.21-29
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• 2005

One way to recycle the construction wastes is to use the waste concrete aggregates as the pavement materials. Although there are many studies and technical developments about waste concrete aggregates, the impurities produced in the process of the aggregate production prevent the use of the waste concrete aggregates in the pavement construction. In this study, the impurities included in the recycled waste aggregates were classified into inorganic and organic ones according to their characteristics, and the influences of each impurities on the pavement performance were presented. It was also showed that the limit of impurity content in the lean concrete base through the correlation between the inorganic impurity content and the compressive strength, and that in the granuler subbase layer through the correlation between the organic impurity content and the modified CBR. In conclusion, it is possible to apply waste concrete aggregates for the pavement when inorganic impurity content is less than 10% in the lean concrete base, and organic impurity content is less than 2% in granular subbase.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.531-538
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• 2013

A mass balance method established in this laboratory was applied to determine the purity of an endosulfan-II pure substance. Gas chromatography-flame ionization detector (GC-FID) was used to measure organic impurities. Total of 10 structurally related organic impurities were detected by GC-FID in the material. Water content was determined to be 0.187% by Karl-Fischer (K-F) coulometry with an oven-drying method. Non-volatile residual impurities was not detected by Thermal gravimetric analysis (TGA) within the detection limit of 0.04% (0.7 ${\mu}g$ in absolute amount). Residual solvents within the substance were determined to be 0.007% in the Endosulfan-II pure substance by running GC-FID after dissolving it with two solvents. The purity of the endosulfan-II was finally assigned to be ($99.17{\pm}0.14$)%. Details of the mass balance method including interpretation and evaluating uncertainties of results from each individual methods and the finally assayed purity were also described.