• The Korean Journal of Ceramics
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• 제2권2호
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• pp.63-69
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• 1996

Barium titanyl oxalates, strontium titanyl oxalates and calcium zirconyl oxalates were prepared with variation of solution concentration and method of adding mixed metal ion solution into oxalic acid. Then they were aged in distilled water, ethanol or methanol, respectively. Barium titanyl oxalates and calcium zironyl oxalates were grown in water and strontium titanyl oxalates were groun in both water and methanol. They were supposed to be grown through the solutionl and reprecipitation mechanism. Nonuniform dispersion of particles in liquid phase is thought to cause abnormal particle growth.

• 한국가금학회지
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• 제49권4호
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• pp.221-228
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• 2022

주요 계란 난백 단백질과 그 가수분해물은 일부 금속 킬레이트 특성을 갖는 기능성 식품 성분으로 알려져 있다. 식이 oxalate를 제거하기 위해 계란 난백 단백질과 그 가수분해물을 이용할 경우 신장 결석을 예방하는데 도움이 될 것이다. 본 연구의 목적은 계란 난백 단백질인 ovalbumin, ovomucin, ovotransferrin과 이 단백질들의 효소처리를 통해 얻은 가수분해물의 biogenic oxalate chelating 활성을 측정하는 것이었다. 채소 중에서 시금치를 과일 중에서 스타푸르트(starfruit)를 선택하여 HCl처리를 거쳐 옥살레이트 추출물(oxalates extract)을 제조하였다. 계란의 난백 단백질 중, ovalbumin, ovomucin, ovotransferrin를 선택하여 이들의 가수분해물과 함께 옥살레이트 추출물과 별도로 혼합하여 3℃에서 24시간 반응을 위한 배양을 시켰다. 원심분리 후 상등액을 HPLC로 분석하여 단백질과 가수분해물의 biogenic oxalate chelating 활성을 비교 분석하였다. 사용된 모든 계란 난백 단백질과 그 가수분해물은 시금치의 oxalates에 대한 biogenic oxalate chelating 활성을 보였다. 그러나열대과일인 starfruit의 oxalates에 대한 킬레이트 활성에서는ovalbumin, hydrolyzed ovalbumin, ovomucin만이 활성을 보였다. 전반적으로, hydrolyzed ovalbumin은 시금치와 스타프루트 모두에서 oxalates chelating 효과가 가장 좋았다. 따라서 계란의 난백 단백질과 그 가수분해물의 옥살산 킬레이트 활성이 있었으며, 식이 옥살산에 대한 영양 개선을 위한 소재로 개발 가능성이 있다. 그러나, 다른 과일과 야채에 대한 옥살레이트 킬레이트 활성과 특정 생체 내 조건에서의 계란 단백질의 옥살레이트 킬레이팅 효과를 검증하기 위한 추가 연구가 필요하다.

• Food Science and Biotechnology
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• 제16권4호
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• pp.650-654
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• 2007

Many vegetables contain oxalate at various levels depending on their type and family. Oxalate is known to reduce mineral bioavailability from foods. The following study was conducted to determine soluble and total oxalate contents in 32 plant samples commonly consumed in Korea using high-performance liquid chromatography (HPLC). Chard, amaranth, and spinach contained total oxalate of >1,000 mg/100 g. Approximately 45% of the oxalate in amaranth is insoluble, whereas 74.46 and 92.45% of the oxalates in chard and spinach, respectively, was soluble oxalates, which may be removed by blanching. Eggplant, carrot, leak, ginger root, spinach, burdock, and sweet pepper contained more than 90% soluble oxalate in total oxalate content. However, all oxalates detected in lettuce and celery were insoluble. Oxalate was not detected in shepherd's purse, bellflower root, garlic, radish root, broccoli, cabbage, onion, lotus root, adlay, cucumber, kale, and pumpkin. These observations provide useful information needed for selection of vegetables.

• 한국해양공학회지
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• 제14권1호
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• pp.37-43
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• 2000

$PbTiO_3$ was prepared by addition of lead-tltanium mixed aqueous solution to an ethanol solution of oxalic acid. The influence of various ripening factors was invesigated. On the basis of the results in the mono-component system we studied the foramtion of $PbTiO_3$ phase with various ripening conditions. The $PbTiO_3$ phase formation was accelerated with the ripening time temperature and ultrasonic irradiation.

• 한국세라믹학회지
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• 제20권2호
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• pp.107-114
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• 1983

Formation of Strontium titanate from the products of coprecipitation takes place at 110$0^{\circ}C$ which is 200-30$0^{\circ}C$ lower than that from mechanical mixtures of $SrCO_3$ and $TiO_2$. This is apparently due to the nature of the compounds formed by the reaction of mixtures of aqueous solutions of $SrCl_2$ and $TiCl_4$ with an ammoniacal solution of ammoni-um carbonate and ammonium hydroxide. A procedure is described for preparing strontium titanyl oxalate tetrahydrate in the several mole ratio of $TiCl_4$ to $SrCl_2$. STrontium titanyl oxalates decompose to titanate at elevated temperature. The coprecipitates and the fired specimen were subjected to examined thermal and X-ray analyses and microstruc-ture by SEM.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.338-339
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• 2017

• Journal of the Korean Wood Science and Technology
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• 제26권1호
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• pp.57-62
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• 1998

In this research, the removal or uptake of heavy metals such as coppers by using oxalic acid metabolism of wood rot fungi, Tyromyces palustris were endeavored. As results, the addition of oxalic acid to copper containing culture did not cause the mycelium growth, but Tyromyces palustris was able to grow in this culture without inhibition. Tyromyces palustris grew with the cicular halo type in copper containing culture, and this type was formed as collectives after examining by microscope, and considered as copper oxalates by analyzing FT-IR comparison experiment with standards. According to this result, Tyromyces palustris has secreted oxalic acid during incubation, this secreted oxalic acid was combined with coppers, and formed copper oxalates by chelating reactions. In other words, the oxalic acid was might be as non-toxifying agent of coppers in medium. By using this copper removal mechanisms, Tyromyces palustris immobilized sawdust was used in bench scale air lift system for removing coppers. The added coppers were almost removed from the system within 72hrs. Therefore, this nonenzymatic wood degradation mechanism may give a possibility for removing coppers from copper containing waste water.

• 대한화학회지
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• 제54권5호
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• pp.603-610
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• 2010

수용액으로부터 3개 양이온 염료(메틸렌 블루 MB, 중성래드 NR, 녹공작석 옥살산염MG)를 제거하는 Maghnia 점토의 흡착제로서의 가능성을 알아보기 위해 접촉시간, pH, 초기 염료 농도, 흡착제 사용량등을 변화시키면서 조사하였다. 적절한 pH는 NR의 경우 6이었고, MB와 MG의 경우 7로 나타났다. 90% 이상의 최대 염료 흡착은 약 60분내에 이루어졌으며, 염료 흡착은 유사 2차반응속도식을 따랐다.

• The Korean Journal of Ceramics
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• 제2권2호
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• pp.70-75
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• 1996

On the basis of growth mechanism proposed by recent work, partile of barium titanyl oxalate was controlled by aging in water. From aging at $25^{\circ}C$ for 3 hours, uniform particles of 0.3 ${\mu}$m were obtained. During aging, abnormal particle growth was observed, which were thought to be caused by impurities in water. With increase of aging time and temperature, particle grows more, and differential growth was promoted. In aging for long time, grown particles were cracked.

• 대한화학회지
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• 제55권2호
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• pp.208-217
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• 2011

Maghnia montmorillonite clay를 이용하여, 두 가지 염료(neutral red; NR과 malachite green oxalates; MG)에 대한 pH 및 온도 효과를 측정하였다. 수용액 속에서 MG는 pH 3-9에서 흡수가 나타나는 반면에, 양이온 NR은 pH 3-5에서 red shift 흡수피크가 나타났으며, 중성 NR은 pH 8-12에서 흡수피크가 얻어졌다. NR에 대해서는 465.13 mg/g, MG에 대해서는 459.89 mg/g의 최대 흡수 피크가 각각 298와 318 K에서 얻어졌으며, 자유에너지 Ea 값은 각각 4.472-5.559 kJ/mol과 2.000-2.886 kJ/mol로 얻어졌다. 도한, as ${\Delta}H^{\circ}$, ${\Delta}S^{\circ}$, ${\Delta}G^{\circ}$ and Ea과 같은 다양한 열역학적인 변수들을 계산했으며, 전체적인 반응의 흡수과정은 자발적이고, 흡열반응으로 진행됨을 알 수 있었다.