• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.379-382
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• 2004

Entomopathogenic nematodes are used for insect control. Herein, an extracellular protease was partially purified from a culture supernatant of Xenorhabdus nematophilus, a symbiotic bacterium of an entomopathogenic nematode, Steinernema glaseri: using precipitation with $80\%$ v/v isopropyl alcohol followed by gel permeation chromatography with a packed Sephacryl S-300 HR media. The partially purified protease exhibited maximal activity at pH 7 in the presence of 1 mM $CaCl_2$. The protease was identified as a metallo-protease based on the inhibition of its activity by the metal chelating agent, EDTA.

• Bulletin of the Korean Chemical Society
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• 제23권5호
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• pp.679-682
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• 2002

Layered Na0.7[Ni0.05Mn0.95]O2 compounds have been synthesized by a sol-gel method, using glycolic acid as a chelating agent. Na0.7[Ni0.05Mn0.95]O2 precursors w ere used to prepare layered lithium manganese oxides by ion exchange for Na by Li, using LiBr in hexanol. Powder X-ray diffraction shows the layered Na0.7[Ni0.05Mn0.95]O2 has an O3 type structure, which exhibits a large reversible capacity of approximately 190 mA h g-1 in the 2.4-4.5 V range. Na0.7[Ni0.05Mn0.95]O2 powders undergo transformation to spinel during cycling.

• Bulletin of the Korean Chemical Society
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• 제23권5호
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• pp.693-698
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• 2002

A method has been described for the determination of Cu(Ⅱ), Pb(Ⅱ), Ni(Ⅱ), Cd(Ⅱ), Mn(Ⅱ) and Fe(Ⅲ) by flame atomic absorption spectrometry (FAAS) after preconcentration on Amberlite XAD-16 resin, using hexamethyleneammonium-hexamethylenedithiocarbamate (HMA-HMDTC) as a chelating agent, and NH3/NH4Cl buffer solution (pH 9). Influences of various analytical parameters such as pH, concentration of nitric acid, amount of analytes, diverse ions and sample volume were investigated. The relative standard deviation (RSD) and the detection limit (LOD) were found in the range of 0.8-2.9% and 0.006-0.277 ㎍/mL,respectively. Recoveries obtained by the column method were quantitative ( >95%) at optimum conditions.The method was applied to the determination of some metal ions in seawater and wastewater samples. A high preconcentration factor (about 150 for seawater and 75 for wastewater samples) and simplicity are the main advantages of this suggested method.

• 산업기술연구
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• 제37권1호
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• pp.12-15
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• 2017

It is important in dentistry that the provisional cement should be cleaned thoroughly from the crown before definitive cementation. The provisional cement has been removed by physical means such as curette, scaler, pumice, or sand-blasting with alumina particles, which is time-consuming, irritating, tedious, even causing crack. To avoid such troubles occurring through such physical cleaning means, the chemical solutions for dissolving the provisional cement remaining in dental crown were prepared, and solubilizing power of the solutions was measured and compared. The solution composed of MEA, NaOH, chloride chemicals ($CHCl_3$, $CCl_4$, $CH_2Cl_2$), surfactants (Igepal, Tween20), chelating agent (EDTA), and Ethyl cellosolve was most effective for dissolving the provisional cement.

• 펄프종이기술
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• 제47권6호
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• pp.81-88
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• 2015

The molecular weight (MW) and crystallinity of cotton linter need to be controlled to be dissolved well in N-methylmorpholine N-oxide (NMMO) solvent for manufacturing regenerated fibers of clothing fabrics. Electron beam irradiation or sulfuric acid pre-treatment followed by alkaline peroxide bleaching has been used to control MW effectively and to improve brightness of cotton linter. Auto-hydrolysis of cotton linter without electron beam irradiation or chemical pre-treatment was found to be effective as an alternative pre-treatment method. Removal of metal ions, that hampered dissolution of cotton linter by NMMO, was also investigated when the auto-hydrolysis was accompanied with ionic polymers and chelating agent.

• 대한화학회지
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• 제24권3호
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• pp.239-244
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• 1980

모나자이트 중의 Y, La, Ce, Pr 및 Nd 들을 pH 8.4에서 EDTA와 착염을 만들어 미리 음이온 교환수지에 EDTA를 흡착시킨 수지관에 용리시켜 희토류 원소들의 분리를 시도하였다. 용리액은 pH 8.4의 EDTA를 사용하였으며, 용리액의 분율에 따라 측정한 각이온의 분리도는 55∼98%이었다.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.208-212
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• 2011

In this work, the calculated nuclear quadrupole coupling constants of $^{17}O$ in some styrylquinoline conformers were presented. The calculations were carried out to find the relationships between the charge distribution of styrylquinolines and their pharmaceutical behavior and to explore the differences among the electronic structures of some conformers of these potent HIV IN inhibitors. Furthermore, the HIV IN inhibitory of R1 and R2 rotamers was compared. On the basis of our results: - Charge density on oxygen atoms of carboxyl moiety has a dominant role in the drug activity. - The a conformer in which a divalent hydrogen atom is a link, has more capability in antiviral drug treatment. - The R1 conformer, as a $Mg^{+2}$ chelating agent, is better than R2 conformer and thus it is more inhibitor of HIV IN.

• Nuclear Engineering and Technology
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• 제14권3호
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• pp.116-121
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• 1982

해조류인 미역(Undaria pinnatifida)에 있어서 해수로부터 Sr-90의 농축 및 잔류현상을 실험실적조건하에서 실험한 바 다음과 같은 결과를 얻었다. 해수로 부터 Sr-90의 농축계수는 식물체의 부위, 노출시간, 해수의 염도, 안정원소인 Ca, Sr의 농도에 따라 달리 나타났다. 해조체내에 한번 흡수된 Sr-90은 깨끗한 해수에 대한 노출시간, Ca의 농도와 킬레이트제의 존재여부에 따라 다시 유출되는 패턴이 달리 나타났다. 해조에 의한 Sr-90의 흡수는 표면흡착에 크게 의존하는 것으로 판단되었다.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.273-281
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• 2010

Nickel recovery method was studied by the wet process from the catalyst used in hydrogenation process. Nickel content in waste catalyst was about 16%. At the waste catalyst leaching system by the alkaline solution, selective leaching of nickel was possible by amine complex formation reaction from ammonia water and ammonium chloride mixed leachate. The best leaching condition of nickel from mixed leachate was acquired at the condition of pH 8. LIX65N as chelating solvent extractant was used to recover nickel from alkaline leachate. The purity of recovered nickel was higher than 99.5%, and the whole quantity of nickel was recovered from amine complex.

• 분석과학
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• 제32권1호
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• pp.1-6
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• 2019

Chinese brake fern (Pteris vittata) has potential for application in the phytoremediation of arsenic introduced by lead arsenate-based pesticides. In this study, Chinese brake ferns were used to extract arsenic, mainly in field and greenhouse experiments, and to assess the performance of simultaneous phytoaccumulation of arsenic and lead from homogenized soil in the greenhouse, with the application of EDTA and electric potential. The ferns have been shown to be effective in accumulating high concentrations of arsenic, and extracting both arsenic and lead from the contaminated soil, with the addition of a chelating agent, EDTA. The maximum increase in lead accumulation in the ferns was 9.2 fold, with a 10 mmol/kg addition of EDTA. In addition, the application of EDTA in combination with electric potential increased the lead accumulation in ferns by 10.6 fold at 5 mmol/kg of EDTA and 40 V (dc), compared to controls. Therefore, under application of EDTA and electric potential, Chinese brake fern is able to extract arsenic and lead simultaneously from soil contaminated by lead arsenate.