• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.248-254
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• 2005

This paper presents a quantitative method of sequential separation of $^{90}Sr,\;^{241}Am$ and Pu nuclides with an anion exchange resin and a Sr-Spec resin. The Pu isotopes were purified with an anion exchange resin. The americium and strontium fractions were separated from the matrix elements with an oxalate co-precipitation method. Americium fraction was separated from the strontium fraction with iron co-precipitation method and purified from lanthanides with anion exchange resin. Strontium-90 was purified from other hindrance elements with the Sr-Spec resin after oxalate co-precipitation. The measurement of Pu and Am isotopes was carried out by an ${\alpha}$-spectrometer. Strontium-90 was measured by a liquid scintillation counter. The radiochemical procedure of $^{90}Sr,\;^{241}Am$ and Pu nuclides investigated in this study has been validated by application to IAEA-Reference soils.

• Journal of the Korean Chemical Society
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• v.20 no.1
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• pp.43-47
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• 1976

The determination of oxalic acid is carried out with Zr(IV)-XO complex by spectrophotometry. The Mechanism of this method in 1∼4N HCl solution is shown below (XO = xylenol orange); Zr(IV)+XO=Zr(IV)-XO+ excess XO, Zr(IV) - XO + oxalate = Zr(IV)-oxalate + XO When oxalic acid is added to Zr(IV)-XO complex(red color), the absorbance of Zr(IV) - XO complex is decreased in proportional to the amount of oxalic acid. The malic, malonic, maleic, fumaric, succinic, folic and glutamic acid did not interfere even if they are present in hundred times of oxalic acid. If they are present in the same amount as oxalic acid, citric and tartaric acid did not interfere but they are interfere when they are present in much more than that of oxalic acid.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.355-363
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• 1998

The oxygen flux of SDC ($Sm_2O_3\;doped\;CeO_2$) solid electrolyte membranes with electronic and oxygen ion-ic conductivities has been investigated as a basic research in order to develop the conversion process of na-tural gas to syngas using the ceramic membrane reactor. Tube type membranes(1 mm thickness) were fa-bricated by slip casting of SDC powders prepared by the oxalate coprecipitaion method. Dense oxygen per-meation membranes(0.1 mm thickness) could be synthesized via sintering at $1450^{\circ}C$ for 2h and their re-lative density was over 95% The oxygen flux through SDC membranes doped 20mol% $Sm_15$ was about $1.13{\times}10^{-5}\;mol/m_2{\cdot}sec$ at low temperature around $800^{\circ}C$. In addition the SDC membranes showed a good thermaal stability for a long period of service.

• Journal of Radiation Protection and Research
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• v.8 no.2
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• pp.36-40
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• 1983

Uranium radionuclides are electrodeposited on inexpensive stainless steel cathode from a mixed oxalate-chloride electrolyte. The factors affecting the optimum condition for the deposition are determined by studying the effects of deposition time, initial current, electrode spacing, pH of electrolyte and uranium concentration in the electrolyte at fixed cathode area. The experiment which was repeated 3 times at each uranium concentration with 60 minutes of deposition time, gave an error of less than 4% standard deviation at the 90% confidence level with average yield greater than 99%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.3
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• pp.252-261
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• 1994

The $(Ba_{1-X}Sr_X)ZrO_3$ powder showing chemically pure and fine particle size was attempted to be synthesized by the oxalate method. The objective of this study is to determine the optimum synthesis condition of stable $(Ba_{1-X}Sr_X)ZrO_3$ powder in terms of the temperatures coefficient of resonant frequency ${\tau}_f$ by examining the microstructure and dielectric properties of the synthesized powder. The six compounds (x=0, 0.2, 0.4, 0.6, 0.8, 1) of $(Ba_{1-X}Sr_X)ZrO_3$ were prepared by the oxalate method, and then calcined at $1000^{\circ}C$ to obtain the crystalline $(Ba_{1-X}Sr_X)ZrO_3$ powder. The synthesized powder showed the globular-shape and average particle size of less than $0.2 \mu\textrm{m}$. The composition of x=0.5, i.e., half of Ba was replaced by Sr, is experted to show the zero value of temperatures coefficient of capacitance ${\tau}_c$.

• Analytical Science and Technology
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• v.12 no.3
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• pp.177-183
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• 1999

The determination method of free acid in spent U-Al nuclear fuel solutions by Gran plot titration was described. Effect of U(VI) and Al(III) on the alkalimetric titration of nitric acid was investigated in oxalate complexing media as well as in noncomplexing media. Positive biases were observed in both titration media when the end-point was estimated by the Gran plot method. It was found that the cause of the bias was U(VI) in the oxalate complexing media, but Al(III) in the noncomplexing media. The relative error was less than 1% in the titration of 0.1 M $HNO_3$ at a U(VI) : Al(III) : $H^+$ mole ratio of up to 2:12:1 as long as the pH of the oxalate titration media was sustained to be below 5.0 at the beginning of titration. The method was successfully applied to the determination of nitric acid in a solution of HANARO reactor fuel with U:Al mole ratio of 1:6.

• Analytical Science and Technology
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• v.18 no.6
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• pp.469-474
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• 2005

This paper presents a quantitative method of sequential separation of $^{90}Sr$, $^{241}Am$ and Pu radionuclides with an anion exchange resin and a Sr-Spec resin. The Pu isotopes were purified with an anion exchange resin. The americium and strontium fractions were separated from the matrix elements with an oxalate co-precipitation method. Americium fraction was separated from the strontium fraction with iron co-precipitation method and purified from lanthanides with anion exchange resin. Strontium-90 was purified from other hindrance elements with the Sr-Spec resin after oxalate co-precipitation. The measurement of Pu and Am isotopes was carried out by an ${\alpha}$-spectrometer. Strontium-90 was measured by a liquid scintillation counter. The radiochemical procedure of $^{90}Sr$, $^{241}Am$ and Pu radionuclides investigated in this study has been validated by application to IAEA-Reference soils.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.584-594
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• 1996

For the separation and purification of aluminium chloride hexahydrate crystals from kaolin leaching solution the effects of crystallization conditions, such as crystallization temperature, concentration of aluminium chloride concentration in the leaching solutin and gas flow rate of HCl into the leaching solution, on purity of the aluminium chloride hexahydrate crystals were investigated. The supersaturation level of aluminium chloride in the leaching solution gave great influence on the purity of the crystals. When supersaturated concentration of the aluminium chloride in the leaching solution was generated in low level, the aluminium chloride hexahydrate crystals were produced with high purity ; that is, the crystals hving a low Fe-ion concentration. The supersaturation level of aluminium chloride in the leaching solution was mainly determined by crystallization temperature, concentrations of aluminium chloride and hydrochloric acid in the solution. However, in spite of changes of the above crystallization coditions, a needle shape morphology of aluminium chloride hexahydrate crystals did not modified. To measure hydrochloric acid concentration in the kaolin leaching solution, we applied the oxalate titration method, which was suggested by shank [9] and it was prove that this method could titrate hydrochloroic acid concentration in multi-component ionic solution such as kaolin leaching solution.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.151-157
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• 2002

The removing copper from CCA, CCFZ treated wood were tested with Tyromyces palustris. The shacking culture, solid culture, and stationary culture methods were tested to removal of copper in CCA, CCFZ treated wood. The steam pressure method and oxalic acid method were tested as pretreatment. To investigate of copper removal mechanism, the oxalic acid that produced by T. palustris and combination with copper was examined on stationary culture that contained CCA and CCFZ treated wood chips. Oxalic acid increased copper removing rate of T. palustris as pretreatment. Stationary culture had most removal effectiveness among the culturing methods. The removal rate of copper on bioreactor was 61% on 7 days. Copper-oxalate was detected on liquid culture, which show the oxalate from liquid of culture combined with copper from treated wood. It would be related to the removal of copper from treated wood by T. palustris.

• YAKHAK HOEJI
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• v.56 no.5
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• pp.288-292
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• 2012

The aim of the paper is to ameliorate old research methods of Korean Pharmaceutical Codex to adjust the newest scientistic level which is necessary to maintain quality of medical supplies effectively. After reviewing result of Establishment of Dissolution Specifications for Generic Drugs in Korea Pharmaceutical Codex Monograph, there are two items chosen for the methods - Establishment of Dissolution Specifications for Generic Drugs in Korea Pharmaceutical Codex Monograph which KFDA researched in 2010, arranged new measuring standard by having an experiment to set measuring method after obtaining each item. According to the result, The experiment includes a measuring method of two items; Nafronyl Oxalate Capsules, and Ticlopidine Hydrochloride Tablets. The research is ameliorated by research methods through several experiments such as High Performance Liquid Chromatography validation, preparing items, implement of trial-experiment and authentic experiment, and experiment on measuring method of regulations of Korea Pharmaceutical Codex. The experiments are taken opinions of experts in KFDA into consideration and wrote out a report of the new measuring method on each last item. The report is combined as each two experiment sections of analyzing method to maintain the quality on the basis of the research in 2010 on setting of dissolution specifications for oral solid dosage forms. The result of measuring method of medical supplies through modernizing trial method of oral solid dosage forms is available to be accurate. In conclusion, this study could contribute to promotion of public health by organizing a basis for safe and high quality of medical supplies in domestic market.