• 한국세라믹학회지
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• 제14권2호
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• pp.82-87
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• 1977

The material used in this experiment is Ha-Dong kaolin whichis composed of almost crystallographically pure meta-halloysite. It was grinded and passed through 250 mesh and 325 mesh. It was treated with oxalic acids and EDTA which are different in concentration. The samples in conical beaker were kept in laboratory incubator at $25^{\circ}C$ for a certain hours. The treated samples were stirred twice a day. The sample in the conditions as A-7 was kept in an autoclave under the pressure of 3 atmospheric. The samples suspended in each solution were kept for 1.5, 3 and 6 months. The transformation of crystals was detected by X-ray spectrometer, electron microscopy, and infrared spectrometer. The sample through 325 mesh compared with one through 250 mesh was transformed much more. It took for 6 months to transfer from halloysite to kaolinite in EDTA, and 3~4 months under 3 atms in autoclave at the same condition. In oxalic acids it took more than 6 months.

• Transactions on Electrical and Electronic Materials
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• 제11권5호
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• pp.230-233
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• 2010

The authors investigated the anodization mechanism of aluminum in an oxalic acid solution, and the electrochemical reaction is very unique for pore formation via the dissolution process, which is very dependent on the surface geometry in nanoporous alumina templates. The cross-sectional nanochannels showed that the geometrical curvature of the initial surface can cause the branching of nanochannels to be adjusted in volume occupancy to be direct to the electric field normal to the surface. The nanoporous alumina with the crystalline $\gamma-Al_2O_3$ phase showed hexagonal ordering at a voltage of 40 V, with a nanohole distance of 102 nm from the charge density oscillation of the oxalic acid solution.

• 한국식품조리과학회지
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• 제9권3호
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• pp.204-209
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• 1993

This investigation was undertaken for the purpose of studying the chemical properties of different kinds of spinach by various blanching procedure. Ascorbic acid, mineral and oxalic acid retention of spinaches, as well as blanch effluent composition were the major factors considered with Dong-cho(winter spinach) and vinylhouse grown spinach. Ash, crude protein, crude fat and vitamin C contents of Dong-cho were higher than those of vinylhouse spinach. On the other hand, vinylhouse grown spinach showed higher content in moisture, phosporous, calcium and oxalic acid. Most of the components in spinaches were decreased by increasing the blanching water volume and time. Reducing sugar and solid content in blanch effluent of Dong-cho were increased by increasing the blanching water volume and time, however, vinylhouse spinach showed no reducing sugar.

• 미생물학회지
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• 제11권2호
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• pp.51-58
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• 1973

Three kinds of organic matter such as glucose, oxalic acid, and ethanol were added to the media(N-free or $NO_{3}$-riched) and their effects on the nitrogen fixation of Nostoc pruniforme were measured by manometric technique through the experiments in vivo. 1) The organic matters used in this experiments showed effective results as a role of substrate for the fixation of atmospheric nitrogen. 2) In the nitrogen-free medium treated with the both of flucose nad ethanol, the highest nitrogen uptakes were detected in the treated of low concentrations (glucose ; 0.1%, 0.5%, ethanol : 0.1%, 0.5%). On the contrary, the highest nitrogen uptakes in $NO_{3}$-riched medium were measured at the treated of high concentrations (glucose ; 2%, 1%, ethanol ; 1.5%, 1.0%). 3) The highest nitrogen uptakes in N-free medium treated with oxalic acid were measured at the concentration of 2% and 1%, respectively. In the medium of $NO_{3}$-riched, the nitrogen uptakes were in the opposite directions.

• Journal of Microbiology and Biotechnology
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• 제3권4호
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• pp.266-269
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• 1993

The production of free non-volatile and volatile organic acids in Kimchi during fermentations at 30, 20 and $5^{\circ}C$, were determined by gas chromatography. The order in the amount of non-volatile organic acid, soon after preparation, was malic, citric, tartaric, pyroglutamic, oxalic, lactic, succinic and ${\alpha}-ketoglutaric$ acids. The major non-volatile acids at the optimum ripening time were malic, tartaric, citric and lactic acids, and as the temperature was lowered, the amount of lactic, succinic, oxalic, pyroglutamic and fumaric acids increased, while that of malic and tartaric acids decreased. The order in the amount of volatile acids at the beginning was acetic, butyric, propionic and formic acids. Among these acids, acetic acid was significantly increased in its amount during fermentation and the Kimchi fermented at low temperature produced more acetic acid than that fermented at high temperature.

• 한국세라믹학회지
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• 제23권4호
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• pp.11-16
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• 1986

$BaTiO_3$ ceramics powder was prepared by coprecipitation method either in oxalic acid solution or in potassium hydroxide solution. Thermal decomposition of coprecipitated $BaTiO(C_2O_4)_2$.$4H_2O$ powder in oxalic acid solution was investigated by means of Themogravimetry Differential Thermal Analysis and X-ray Diffraction Analysis. Low temperature decomposition of coprecipitated $BaTiO(C_2O_4)_2$.$4H_2O$ caused narrow particle size distribution whereas high temperature decomposition caused fairly wide particle size distribution by partial sintering. As the reaction time increased the average particle size of coprecipitated $BaTiO_3$ powder in KOH solution was increased. The most narrow paticle size distribution was obtained when the coprecipi-tates were ripened for 4hrs.

• 식품산업과 영양
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• 제7권2호
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• pp.40-44
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• 2002

매실의 향기성분은 50여종 중 알콜류가 benzyl alcohol, linalool, 1,6-octadien-3-ol, n-haxanol 등 10종, aldehyde류가 2-hexenal, benzaldehyde, n-hexanal 등 3종, acid류가 butandeionic acid, acetic acid, 2종, 2-iodo-hexane 등 hydrocarbon류가 5종, butanedioic acid-diethyl estet를 포함한 ester류가 3종, B-ionone을 포함한 ketone류가 3종 그리고 기타 성분이 2종이었다. 매실이 성숙함에 따라 향기성분의 수가 증가하고 그 함량도 증가하는 경향이었다. 매실의 비휘발성 유기산의 조성은 succinic, fumaric, oxalic, malic, tartaric 및 citric acid이었다. 매실이 비휘발성 유기산은 성숙 초기에는 malic acid와 oxalic acid의 함량이 높았다. Citric acid의 함량이 증가한 반면에 대부분의 유기산은 감소하는 경향이었다. 휘발성 유기산은 성숙중에 formic acid함량은 감소하고 butyric acid의 함량은 증가하는 경향이었다. 총 유기산의 함량은 매실 성숙에 현저히 감소하는 경향이었다.

• 한국축산식품학회지
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• 제21권1호
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• pp.64-70
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• 2001

The extraction procedure and HPLC condition were modified to analyze the residues of oxytetracycline, sulfamethoxazole and chloramphenicol in pork, simultaneously. The antibacterial agents in pork were extracted with 0.02M EDTA-Mcilivine buffer:ethanol:acetonitrile (5:3:2). After the removal of fat with n-hexane, the extracts were evaporated and purified with Sep-pak $C_{18}$ cartridge column using 0.01M oxalic acid 0.1% (v/v) triethylamine (TEA) in acetonitrile. The peak of antibacterial agents was detected with $\mu$ Bondapak C18 column, UV detector (280nm) and 0.01M oxalic acid: methanol: acetonitrile (7.5:2.0:0.5). Detection limits for three antibacterial standards were 0.03 ppm. Calibration curves were linear between 0.03 and 2.0 ppm (R$^2$>0.999). When spiked the level of 1.0 ppm of oxytetracycline, sulfamethoxazole and chloramphenicol into meats, the recoveries from meats were 77.3%, 79.7% and 59.3%, respectively. These results showed that the modified extraction method provided good analytical resolution and the recoveries of the above antibacterial agents in meats.

• 공업화학
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• 제22권5호
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• pp.514-517
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• 2011

본 실험에서는 옥살산과 알코올계 용매를 사용하여 마그네슘 호일의 화학적 식각에 의해서 마그네슘 옥살레이트(Magnesium oxalate) 나노구조를 제조하였다. 알코올계 용매 중 에탄올 용매에서 마그네슘 옥살레이트 나노와이어를 얻을 수 있었다. 시간에 따른 나노와이어의 형성 과정을 살펴보았고, FE-SEM을 통하여 형상을 살펴보았다. TGA 분석을 통하여 열처리 조건을 결정하였다. 열처리를 통하여 마그네슘 옥살레이트 나노와이어에서 산화마그네슘(MgO) 나노와이어로 전환시켰고, 이를 FE-SEM과 FT-IR을 통하여 확인하였다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.424-425
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• 2018