• Journal of Food Hygiene and Safety
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• v.8 no.1
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• pp.25-35
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• 1993

This study is conducted to deyelop more conyenient simultaneous determination method by HPLC for mixed antimicrobial agents (sulfamerazine; SMR, sulfamethazine; SMT, sulfamonomethoxine; SMMX, sulfadimethoxine; SDMX, sulfaquinoxaline; SQX, furazolidone; FZ, zolene; ZOL and ethopabate; EPB in muscles of boline, pork and chicken. The drugs were extracted by dichloromethane and water. The extract, after solyent eyaporation, was partitioned in hexane/water and water/dichloromethane. The dichloromethane layer was filtrated with anhydrous $Na_5S0_4\;in\;_3G_3$ glass filter and was eyaporated to dryness. The residue was dissoIYed in mobile phase. The test solution analyzed by HPLC. The chromatograpic conditions were as follows; Column-Spheri 5 RP-8($4.6{\times}220,\;5\;{\mu}$), Wayelength-270 nm, Mobile phase-acetonitrile: 0.005 M oxalic acid (22 : 78). The ayerage recoyeries of drugs from muscles of boline, pork and chicken spiked standard solution were approximately 74~99%, 73~99% and 75~96%, respectiyely. The limits of detection were 5 ppb for SMR, SMT, SMMX, SDMX and EPB, and 8 ppb for SQX, FZ and ZOL.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.127-132
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• 2010

Biomphalaria alexandrina snails play an indispensable role in transmission of schistosomiasis. Infection rates in field populations of snails are routinely determined by cercarial shedding neglecting prepatent snail infections, because of lack of a suitable method for diagnosis. The present study aimed at separation and quantification of oxalic, malic, acetic, pyruvic, and fumaric acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to test the potentiality of these acids to be used as diagnostic and therapeutic biomarkers. The assay was done in both hemolymph and digestive gland-gonad complex (DGG) samples in a total of 300 B. alexandrina snails. All of the studied acids in both the hemolymph and tissue samples except for the fumaric acid in hemolymph appeared to be good diagnostic biomarkers as they provide not only a good discrimination between the infected snails from the control but also between the studied stages of infection from each other. The most sensitive discriminating acid was malic acid in hemolymph samples as it showed the highest F-ratio. Using the Z-score, malic acid was found to be a good potential therapeutic biomarker in the prepatency stage, oxalic acid and acetic acid in the stage of patency, and malic acid and acetic acid at 2 weeks after patency. Quantification of carboxylic acids, using HPLC strategy, was fast, easy, and accurate in prediction of infected and uninfected snails and possibly to detect the stage of infection. It seems also useful for detection of the most suitable acids to be used as drug targets.

• Analytical Science and Technology
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• v.14 no.1
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• pp.34-43
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• 2001

The present work is aimed to evaluate the conditions of the hydride generation (HG) for germanium analysis by inductively coupled plasma (ICP)-atomic emission spectrometry (AES). Twelve different kinds of acids were used such as phosphoric, hydrochloric, nitric, sulfuric, perchloric, boric, tartaric, malic, oxalic, tannic, citric, and acetic acid. It was found that phosphoric acid yielded the maximum efficiency of hydride generation. Also, efficient hydride generation was obtined with the buffer solutions containing phosphate ions over a wide range of pH. In addition, in the presence of phosphoric acid the interference caused by metals was suppressed in the hydride generation of germanium. As the concentrations of a reducing agent and a stabilizing increased the hydride generation efficiency and the acid concentration proviaing the maximum intensity were increased. By using an analytical method developed in this study, the contents of germanium in water and rock samples were determined. The detection limit of germanium in the presence of phosphoric acid was $0.03{\mu}g/L$.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.876-885
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• 2018

Utilization of spent RHDM(Residue Hydrodemetallation) catalyst as de-NOx SCR(Selective Catalytic Reduction) catalyst was studied by conducting by heptane cleaning and high-temperature roasting for removal of deposited carbon and sulfur. Followed by oxalic acid leaching was carried out for controlling excess vanadium deposited on spent RHDM catalyst in search of appropriate vanadium loadings for the best SCR performance and the leaching conditions are 5~15wt% concentration of oxalic acid and 5min leaching time at $50^{\circ}C$ with the ultra-sonic agitator. De-NOx activities of prepared and commercial SCR catalyst were measured by the atmospheric SCR catalyst performance test unit, their residual content were also carried out by ICP, C&S Analysis and XRF. Acid leaching (AL-10) catalyst showed the highest de-NOx efficiency of all prepared catalysts and the de-NOx efficiency over wash coated catalyst(WC-AL-10) was equivalent to that of commercial SCR catalyst. Therefore the possibility of using as SCR catalyst for each application by adjusting treatment conditions of spent RHDM catalyst was found and further research will be needed in detail for the its commercialization.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.808-816
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• 2008

In the present paper, a study has been performed on remediating mine tailings around abandoned mine contaminated with high concentrations of arsenic and heavy metals using the technique of soil washing. Through the removal experiment of arsenic, the optimal conditions in the type and concentration of washing reagent, mixing ratio of mine tailings and washing reagent, and washing time were derived. Results showed that the most effective washing reagents to remove arsenic from mine tailings were oxalic acid(72% removal efficiency) and phosphoric acid(65%), while the oxalic acid(89%) was the most effective in removing the heavy metals containing Cu. In addition, the most economical and efficient washing concentration was 0.25 M and the most suitable washing time was 30 minutes. The optimal mixing ratio of mine tailings and washing reagent was 1 : 20(mass/vol) from the viewpoint of minimization of wastewater produced after the washing, as well as the washing effectiveness. Although the mixture of washing reagents did not help in removal of arsenic, it could lead to much elevated synergy effect on removing Cu and Zn, compared with the single reagent.

• 보존과학연구
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• s.34
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• pp.110-122
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• 2013

The Seven-story Stone Pagoda of Jeongamsa Temple consists of dolomitic limestone. The surface of the stone stupa is efflorescene. There are spaces between parts in the stereobate and part of roof at the fifth story and above. The space between parts is colonized by biological contaminants. There are breakaway parts in the third, fifth, sixth, seventh story. The dry and wet cleaning of all the biological contaminants, efflorescene. The steam cleaning of rest of efflorescene. The use of poultice with oxalic acid, were done to remove the rust. Breakaway parts are inosculated by L30 and Por-rok. Spaces between parts are waterproofing by Porrok. After treatment, the efflorescene of part of waterproofing are comparatively scarce. So waterproofing is effective at reduced efflorescene and waterproof.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.2
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• pp.221-227
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• 1996

This study was performed to analyze general components such as, organic acids, alcohols and minerals In persimmon vinegar made with quick fermented using deteriorated sweet persimmon and four commercial vinegars (rice vinegar, apple vinegar, brewed vinegar, traditional persimmon vinegar) purchased In local markets for quality evaluation. The pH and total acidity of all vinegars were in the range of 2.02-3.02 and 4.62-9.78%, respectively The pH of quick fermented persimmon vinegar (A) was relatively higher than that of others. Acidity was the highest in brewed vinegar. Total sugar content was in the range of 0.45-6.43%. These contents were high In were high In traditional persimmon vinegar wherase low in brewed vinegar. Total nitrogen and amino-nitrogen were in the range of 0.025-0.046% and 0.015-0.029%. Organic acids were identified as acetic acid, citric acid, tartaric acid malic acid, succinic acid, formic acid and oxalic acid. While major minerals of all vinegars were Mg, Ca, and Na, minor minerals were Zn, Cu, Mn and Fe.

• Journal of the Korean Society of Tobacco Science
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• v.28 no.2
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• pp.75-82
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• 2006

This study was carried out to investigate the changes of free sugars, non-volatile organic and fatty acids in flue-cured leaf tobacco during aging. The threshed leaf tobacco(B1O and C1L) produced in 2002 crop year was aged for 21 month in warehouse of Oc-Cheon Leaf Tobacco Processing Factory. The leaf tobacco were sampled at three month intervals for analysis of free sugars, non-volatile organic and fatty acids. The major free sugars of flue-cured were glucose and fructose regardless of tobacco grades. After aging period of 21 months, the contents of glucose and fructose showed a tendency to slightly decrease, and there was no appreciable change in the contents of sucrose in B1O and C1L grades. The major compound of non-volatile organic acid and fatty acid were malic, oxalic and citric, linolenic, linoleic and palmitic acid regardless of tobacco grade. After aging period of 21 months, the contents of malic, malonic, oxalic and fumaric acid showed a tendency to slightly decrease, whereas succinic acid was slightly increased, and maleic acid was not changed in B1O and C1L grades. The decreases in fatty acid contents in B1O and C1L grade tobacco loaves after 21 month aging were 16.5% and 9.8%, respectively. The decreases in linolenic acid contents in two grades were the highest, showing 22.1% and 12.0% reduction after 21 month aging.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.2
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• pp.85-90
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• 2018

For the recovering rare earths in the spent nickel-metal hydride batteries, 10 M NaOH is added to the solution leached with sulfuric acid. The rare earth powders were precipitated at rate of 98 % at the condition of pH 2.0 or less. The recovered rare earth complex precipitate increased the leaching rate to nitric acid by heat treatment at $800^{\circ}C$ for 4 hours. Subsequently secondary precipitation was performed by adding oxalic acid to the solution in which the rare earth complex precipitate was dissolved. The re-precipitated rare earth powders were converted into oxide form through heat treatment at $800^{\circ}C$ for 4 hours with purity of 99.5 %.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.226-232
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• 2014

In this study, we investigated kinetic model for the acid-catalyzed xylan hydrolysis at temperature $120{\sim}150^{\circ}C$. Also, we analyzed the kinetic parameters for xylose production and furfural decomposition. The hydrolysis of xylan and the degradation of xylose were promoted by high reaction temperature and acid concentration. The optimal hydrolysis condition for the highest reaction rate constants ($k_1$) was different depending on the acid catalysts. Among sulfuric, oxalic and maleic acid, the xylan reaction rate constants ($k_1$) to xylose had the highest value of $0.0241min^{-1}$ when 100 mM sulfuric acid was used at $120^{\circ}C$. However, sulfuric acid induced more xylose degradation compared to oxalic and maleic acid hydrolysis. The activation energy for xylan degradation was the highest when sulfuric acid was used.