• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.236-243
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• 2009

Proton Engineering Frontier Project (PEFP) has supplied the metal ions to users by using an installed metal ion implanter of 120 keV. At present a feasibility study is being performed for a cobalt ion implantation. For a cobalt ion extraction we studied to sustain the high temperature($648^{\circ}C$) for metal ions vaporization from a cobalt chloride powder by using an alumina crucible in the ion source. The temperature condition of the crucible was satisfied with the plasma generation at the arc current of 120V and EHC power of 250W. The extracted beam current of $Co^+$ ions was dependent on the arc current in the plasma. The maximum beam current was $100{\mu}A$ at 0.18A of the arc current. The 3 peak currents of the extracted ions such as $Co^+$, $CoCl^+$ and $Cl^+$ were obtained by adjusting a mass analyzing magnet and the $Co^+$ ion beam peak current fraction as around 70% in the sum of the peak currents. The fluence of the implanted cobalt ions at the $10{\mu}A$ of the beam current and 90 minutes of the implantation time into an aluminum sample as measured around $1.74{\times}10^{17}#/cm^2$ by a quantitative analysis method of RBS (Rutherford Backscattering Spectrometry).

• Journal of the Korean Chemical Society
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• v.39 no.7
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• pp.524-529
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• 1995

The separation efficiency of metal ions by using silica gel bonded 15-crown-5 (SGBM) has been determined by column chromatography in aqueous solution at pH 1. Bindinng constants and separation factors for several SGBM-Metal interactions were measured in aqueous solution. The order of these binding constants and separation factors with metal ions was Li(Ⅰ) < Sr(Ⅱ) < Na(Ⅰ) < Cu(Ⅱ) < Mg(Ⅱ) < K(Ⅰ) < Ca(Ⅱ) < Bi(Ⅲ) < Sb(Ⅲ). These results were explained in terms of the size effect and electron density effect. This experimental results showed good efficiency for separation of $Sb^{3+}$ from mixtures of alkali, alkaline earth metal ions, and $Cu^{2+}$ in aqueous solution.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.511-516
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• 1999

Shiff Base ligand such as [NOIPH] have been synthesized from 2-hydroxy-1-naphthaldehyde and arometic amine. Co(II), Ni(II), and Cu(II) complexes from the reaction metal salts with Tridentate Schiff Base [NOIPH] were sythesized. The ligand and metal(II) complexes were characterized by the elementary analysis, IR, UV-Vis, NMR spectra, and thermogravimetric analysis. Metal(II) complexes in solid state have been shown that the mole raio of Schiff base [NOIPH] as $N_2O$ type to Metal(II) is 2:1 and the metal(II) complexes of $N_2O$ ligand type were four-coordinated configuration.

• Membrane Journal
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• v.12 no.1
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• pp.51-53
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• 2002

The hydrogen ions in poly (vinyl alcohol) (PVA)/sulfosuccinic acid (SSA) membranes substiuted with $Li^+, Na^+, and K^+/ $of monvoalent metal ions, $Mg^{2+}, Ca^{2+} and Ba^{2+}$ of divalent metal ions, and $Al^{3+}$ of trivalent metal ion. In addition, $Li^+ ions were exchanged with varing reaction time. The effects of metal ions exchanged were investigated in terms of methanol permeability -uling diffusion cell. The methanol permeabilies decreased in the sequence of $Na^+, Li^+ and K^+$ and this might be due to the 'Salting-out' effect while the methanol permeabilities for divalent and trivalent ion-substituted membranes were affected by the combined effects of salting-out, eletrostatic crosslinking and extent of metal ion substiution. As for $Li^+$ ions, methanol permeabilities of PVA/SSA membranes decreased in proportion to the degrees of subsituted $Li^+$ ions.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.266-272
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• 1992

Azacrownoalkyl phenylphosphinic acids were synthesized and their competitive solvent extraction characteristics from water to chloroform layer were investigated. Phosphinic acids were synthesized in good yields by one step reaction of phenylphosphinate, aldehyde, and monoazacrown ether and then basic hydrolysis of the resulting phosphinate dsters. These complexing agents revealed a wide effective pH range in extraction of alkali metal ions from water to the organic phase and total metal ion loading at pH 11 was about 75%. The selectivity of the cation extraction was determined mainly by the cavity size of the azacrown ethers, showing $Na^+$ >> $K^+$ > $Rb^+$ > $Li^+$ > $Cs^+$ for the alkyl phenylphosphinic acid ${\underline{2}}$, containing monoaza-15-crown-5 and $K^+$ >> $Rb^+$ > $Na^+$ > $Cs^+$ > $Li^+$ for the alkyl phenylphosphinic acid, ${\underline{3}}$, containing monoaza-18-crown-6 moiety. Applicable pH range of these azacrown ether phosphinic acids in solvent extraction of alkali metal cations was wider than a crownether carboxylic acid with similar selectivity, showing considerable amount of metal ion loading in slightly acidic or neutral media.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.231-240
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• 2002

Microbial metal reduction influences the biogeochemical cycles of carbon and metals as well as plays an important role in the bioremediation of metals, radionuclides, and organic contaminants. The use of bacteria to facilitate the production of magnetite nanoparticles and the formation of carbonate minerals may provide new biotechnological processes for material synthesis and carbon sequestration. Metal-reducing bacteria were isolated from a variety of extreme environments, such as deep terrestrial subsurface, deep marine sediments, water near Hydrothemal vents, and alkaline ponds. Metal-reducing bacteria isolated from diverse extreme environments were able to reduce Fe(III), Mn(IV), Cr(VI), Co(III), and U(VI) using short chain fatty acids and/or hydrogen as the electron donors. These bacteria exhibited diverse mineral precipitation capabilities including the formation of magnetite ($Fe_3$$O_4$), siderite ($FeCO_3$), calcite ($CaCO_3$), rhodochrosite ($MnCO_3$), vivianite [$Fe_3$($PO_4$)$_2$ .$8H_2$O], and uraninite ($UO_2$). Geochemical and environmental factors such as atmospheres, chemical milieu, and species of bacteria affected the extent of Fe(III)-reduction as well as the mineralogy and morphology of the crystalline iron mineral phases. Thermophilic bacteria use amorphous Fe(III)-oxyhydroxide plus metals (Co, Cr, Ni) as an electron acceptor and organic carbon as an electron donor to synthesize metal-substituted magnetite. Metal reducing bacteria were capable of $CO_2$conversion Into sparingly soluble carbonate minerals, such as siderite and calcite using amorphous Fe(III)-oxyhydroxide or metal-rich fly ash. These results indicate that microbial Fe(III)-reduction may not only play important roles in iron and carbon biogeochemistry in natural environments, but also be potentially useful f3r the synthesis of submicron-sized ferromagnetic materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.267-271
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• 1998

In order to investigate the physical properties of alginate extracted from sea tangle, Laminaria app., under various conditions, viscosity and binding capacity of metal ion (BCMI) of alginate were measured. The higher concentrations of sodium carbonate and the longer extracting time became, the lower apparent viscosity and BCMI were. BCMI in alginate reached maximum at the concentration of 0.06M metal ion. The BCMI of $Pb^{++}$ ion was the highest but $Cu^{++}$ ion was the lowest in the five metal ions. BCMI was increased in proportion as increase of viscosity in alginate.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.29-38
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• 2014

G-quadruplex를 형성하는 DNA연속체는 텔로미어에서 발견된다. 지금까지의 연구 결과에 따르면 G-quadruplex는 다양한 유전질환과 암과의 상관관계가 있으며, 따라서 G-quadruplex에 대한 연구는 제약 개발 분야에서 활발하게 진행되고 있다. G-quadruplex는 두 개 이상의 G-tetrad들이 쌓여서 형성된 복합체를 의미하며, G-tetrad란 4개의 구아닌 염기들이 Hoogsteen의 수소결합 통해, 정사각형의 평면을 이룬 물질을 일컫는다. 이때, 알칼리 금속 이온이 G-quadruplex에서의 G-tetrad 복합체 형성에 중요한 역할을 한다는 선행연구 결과가 있다. 특히, 알칼리 금속 중 $K^+$이 가장 G-quadruplex와 결합을 잘 한다고 알려져 있는데 그 이유에 대한 분자적 관점의 설명이 이루어져 있지 않다. 따라서 본 연구에서는 먼저 G-quadruplex의 기본 구성 단위 구조인 G-tetrad와 알칼리 금속 결합체들의 수용액상에서의 구조적, 열역학적 특징을 정량적으로 비교, 분석하였다. 또한, 양자화학적 방법으로 계산된 수용액 상태에서의 결합구조에 대한 용매화 자유 에너지 계산을 수행하여 G-quadruplex 간의 자기 조립 (self-assembly) 현상을 설명하였다.

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.127-132
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• 1983

The catalytic activity of ZSM-5 catalyst for the disproportionation of toluene is dependent on the type of cation exchanged, the degree of ion-exchange and the reaction temperature. The activity increases in the order of alkaline-, alkali earth-, hydrogen, and rare-earth-exchanged ZSM-5 and decreases with increasing degree of cation exchange. Among the ion-exchanged ZSM-5 catalyst, only Cs-ZSM-5 shows predominant selectivity for p-xylene. The selectivity increases with increasing degree of $Cs^+$-exchange and decreasing reaction temperature. This phenomenon is interpreted in terms of shape selectivity arising from the partial blocking of channel intersections by large cesium ions.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.84-85
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• 1994

본 연구는 수용상에 포함된 중금속이온중 에멀젼 액막법(Emulsion Liquid Membranes, ELM)을 이용하여 납이온을 제거시키기 위한 연구이다. 지금까지 수용액상의 중금속 이온의 제거는 전통적으로 이온 침전법을 사용하여 왔다. 그러나 이 방법은 스럿지 처리문제가 남아 있고 식수로 이용되는 수처리에는 식수기준 만족도 때문데 적합하지 않았다. ELM법에 의한 금속이온 제거처리는 전기도금에 의하여 중금속이온을 회수할 수 있고 고도의 수처리를 가능케하여 최근 많은 관심을 갖고 있다. 본 연구에서는 납 이온 추출제로서 D2EPHA와 Alamine336의 이온교환제를 사용하여, 이 씨스테므이 추출 평형자료를 구하고 pH, 추출제의 농도, 교반속도, 에멀젼비율등에 의한 추출효과등을 검토하였다. 또한 2단계 추출 방법을 사용하여 금속이온추출에서 가장 큰 문제점인 유기상 용액의 leakage를 해결하고자 하였다.