• Bulletin of the Korean Chemical Society
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• 제16권4호
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• pp.316-320
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• 1995

The incorporation of metal ion into the Langmuir-Blodgett (LB) film of an itaconate copolymer was investigated. The polymer was prepared via radical copolymerization of monooctadecyl itaconate with triethyleneglycol methyl vinyl ether. The metal ions employed were Na+, Cs+, Mg2+, Fe2+, Al3+, and Fe3+. The surface pressure-area isotherms indicated that all the monolayers studied on subphases with metal ions showed more expanded areas than that observed on pure water. The monolayers showed an irreversible collapse behavior. The collapse pressure of the monolayers was low on subphases containing trivalent metal ions. From the FT-IR spectra by reflection and transmission modes, the formation of carboxylate salts and the uprisen orientation of the pendant against substrate surface in the polymer LB film were determined. It was estimated by XPS measurement that ca. 13.1 repeat units of the polymer contain one Na+ ion, while one Mg2+ ion corresponds to 5.9 carboxyls.

• 한국자기학회지
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• 제13권4호
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• pp.171-175
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• 2003

Czochralski방법으로 성장된 정비조성 LiTaO$_3$ 단결정내에 불순물로 첨가되어 있는 Fe$^{3+}$ 이온에 대하여 상온에서 전자 상자성 공명(EPR : Electron Paramagnetic Resonance) 실험을 실행하였다. X-band(9.447 ㎓) 스펙트로미터를 사용하여 Fe$^{3+}$ 이온에 대한 공명 흡수선을 결정학적 주평면에서 시료를 돌려가면서 자기장을 가하여 각도의존 데이터를 얻었다. 이렇게 얻은 공명 자기장을 유효 스핀하밀토니안을 사용하여 분광학적 분리인자 g 및 영자기장 갈라지기(ZFS: Zero Field Splitting) 상수 b$_{2}$sup 0/ (=D)를 계산하였다. 분석결과 정비조성으로 성장시킨 LiTaO$_3$ 단결정에서 얻은 Fe$^{3+}$ 공명중심은 기존에 발표된 congruent 조성으로 성장시킨 단결정의 것과는 다른 것으로 밝혀졌다. 또한 Fe$^{3+}$ 이온에 관한 온도의존 공명 흡수선을 분석한 결과 실험 온도 구간에서는 LiTaO$_3$ 단결정의 어떠한 상변화도 없는 것으로 나타났다.

• 열처리공학회지
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• 제9권2호
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• pp.130-138
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• 1996

It has been investigated that the ion nitriding effects of a STD61 steel in various time conditions of 3 to 9 hours, and the microstructure of compound and diffusion layers of the ion nitrided specimen for 6 hours and subsequently reheated for 1 hour at various temperatures of $400{\sim}800^{\circ}C$ As the nitriding time increased, the thickness of compound and diffusion layers was increased, but the hardness of surface was not considerably increased (Max Hv=1045 at 9hrs). Some of the nitrogen was denitrided out of the surfac and diffused into the core, and also the oxides ($Fe_3O_4$, $Fe_2O_3$) were formed on the surface of the specimen during reheating. The compound layer was partially decomposed at about $600^{\circ}C$ but the diffusion layer was increased up to $800^{\circ}C$. With increasing reheated temperture, the hardness of the surface was decreased, whereas the hardness depth of diffusion layer (0.25mm) was increased up to $600^{\circ}C$ more than that of ion nitrided (0.18mm). The blend-heat treated STD61 steel by ion nitriding is therefore expected to hold on the characteristics of ion nitriding up to $600^{\circ}C$.

• Applied Science and Convergence Technology
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• 제27권3호
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• pp.47-51
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• 2018

We fabricated an anode-type ion beam source and studied its driving characteristics of the initial extraction of ions using two driving mechanisms: a diffusion phenomenon and a charge repulsion phenomenon. For specimen exposed to the ion beam in two methods, the surface impurity element was investigated by using X-ray photoelectron spectroscopy. Upon Ar gas injection for plasma generation the ion beam source was operated for 48 hours. We found a Fe 2p peak 5.4 at. % in the initial ions by the diffusion mechanism while no indication of Fe in the ions released in the charge repulsion mechanism. As for a long operation of 200 min, the temperature of ion beam sources was measured to increase at the rate of ${\sim}0.1^{\circ}C/min$ and kept at the initial value of $27^{\circ}C$ for driving by diffusion and charge repulsion mechanism, respectively. In this study, we confirmed that the ion beam source driven by the charge repulsion mechanism was very efficient for a long operation as proved by little electrode damage and thermal stability.

• 한국표면공학회지
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• 제19권4호
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• pp.133-139
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• 1986

The effects of alternating voltage, $Cl^-$ ion and pH on the corrosion of Zn and Zn-Fe alloys have been investigated by using electrochemical techniques in $Ca(OH)_2$ solutions. The passive film $Zn(OH)_2$ was initially formed on the Zn surface and gradually transformed to $Ca(Zn(OH)_3)_2{\cdot}2H_2O$, which was identified with the X-ray diffraction method, SEM micrograph and EPMA. The passivity current increased with increasing alternating voltage and decrease AC frequency. ${\xi}$ phase in Zn-Fe alloys reduced the effects of AC. The effect of $Cl^-$ ion on the passivity current of Zn was similar to the AC effect, resulting in pits on Zn. It was also found that the passive region of Zn decreased rapidly below pH 10.3 of the solution.

• Bulletin of the Korean Chemical Society
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• 제11권4호
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• pp.318-323
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• 1990

The bis(malonato)diaquochromate(III) ion, $Cr(C_3H_2O_4)_2^-$ in acidic solution hydrolyzes to give $Cr(C_3H_2O_4)^{+}.$ This reaction is catalyzed by ferric ion and the rate law for this cation catalyzed-aquation in a $HClO_4/NaClO_4$ medium, $I = 1.00 M, is-d[Cr(C_3H_2O_4)_2^-]/dt = ({\kappa}_1[Fe^{3+}] + {\kappa}_2[H^+])[Cr(C_3H_2O_4)_2^-]$ where ${\kappa}_1(25^{\circ}C) = 4.72×10^{-5} M^{-1}sec^{-1} ({\Delta}H^{\neq} = 22.5 Kcal/mol, {\Delta}S^{\neq} = - 2.58 eu) and {\kappa}_2(25^{\circ}C) = 4.75{\times}10^{-5} M^{-1}sec^{-1} ({\Delta}H^{\neq} = 21.2 Kcal/mol, {\Delta}S^{\neq} = - 7.13 eu).$ Rapid preequilibrium association of basic Cr-bound oxygen with $Fe^{3+},$ followed by rate-determining ring opening, is proposed to account for the ${\kappa}_1,$ hydrolysis pathway.

• 한국표면공학회지
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• 제44권4호
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• pp.149-154
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• 2011

Martensitic stainless steel STS 431 has been nitrided by active screen ion nitriding under the various temperature and time. The thickness of diffusion layer, case depth, hardness and composition phases were investigated using field emission scanning electron microscopy (FE-SEM), micro-Vickers hardness tester, X-ray diffraction (XRD) and glow discharge spectroscopy (GDS). It was observed that the thickness of diffusion layer depends strongly on the treatment temperature and time. A sample, which was nitrided at $450^{\circ}C$ for 8hours, was a maximum hardness of Hv0.01 1558 and nitride layer of $70{\mu}m$. As shown in XRD patterns, $\varepsilon(Fe_{2-3}N)$ and expanded martensite (${\alpha}_N$) phases which was saturated with nitrogen solid solution were in the nitrided layer treated at $450^{\circ}C$ for 2 hours. Composition phases of $\varepsilon$ $(Fe_{2-3}N)$ and ${\gamma}'$ ($Fe_4N$) were observed after active screen nitriding at $450^{\circ}C$ for 8 hours.

• KSBB Journal
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• 제9권3호
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• pp.279-286
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• 1994

Fe(III) IDA -PEG/ dextran 액 이상 분계 시스템에서 phosphoprotein의 분배 예측을 위한 모델식이 유도되었다. 본 모델식에는 단백칠 분배에 수소이온과 hydroxide 이온의 저해효과가 포함되어 었다. 표변에 각각 1,27~의 phosphoryl 그 룹을 갖고 있는 ovalbumin의 AI, A2, 성분을 정제한 후 단백질 분배 실험을 수행하였으며 실 험결과와 모텔식에의한 예측이 잘 얼치하는 것 을 확인하였다. Fe(III)IDA-PEG와 단백질 표면 p phosphoryl group과의 결합상수는 PEG 상과 dextran상에 셔 각각 $6.1{\times}, 10^3M^{-1} and 2.3{\times}10^4M^{-1}$이었으며,이것은 Cu(II)IDA-PEG와 단백질 표면 histidine과의 결합상수 보다 3-5배 높은 값이 였 다.

• 한국환경보건학회지
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• 제20권2호
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• pp.73-79
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• 1994

The effects of packing materials in the anaerobic reactor and inorganic chemicals in the synthetic wastewater on the anaerobic treatment during the start up period were investigated using anaeroic filter process. The Ringlace and Honeycomb tube as packing materials were used in the anaerobic reactors. The Ca$^{2+}$ and Fe$^{2+}$ ion concentration as inorganic chemicals contained higher 40 times and 100 times as compared to the control synthetic wastewater, respectively. A start up period 104 and 150 days were necessary to achieve loading rate of 0.37 and 0.74 kg-Toc/m$^3$.d in the anaerobic filter process packed by Ringlace and Honeycomb tube, respectively. The loading rates of the reactor using the synthetic wastewater containing Ca$^{2+}$ (40 times) could be increased faster than in the reactors using the synthetic wastewater containing Fe$^{2+}$ ion (100 times) and control synthetic wastewater. The results of XMA analysis that a lot of the Ca$^{2+}$ ion on the surface of the anaerobic sludge in the anaerobic reactor packed by Ringlace which were fed supplied with synthetic wastewater containing Ca$^{2+}$ ion (40 times) observed as compared to the reactors supplied with control synthetic wastewater and containing Fe$^{2+}$ ion (100 times).

• 환경위생공학
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• 제22권3호
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• pp.77-87
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• 2007

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 - divinylbenzene(DVB) with 1%, 3%, and 5%-crosslinking and macro cyclic ligand of OenNen-$H_4$ by copolymerization method and the adsorption characteristics of uranium(VI), iron(II) and samarium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The uranium ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium ${UO_2}^{2+}>Fe^{2+}>Sm^{3+}$ ion. The adsorption was in order of 1%, 3%, and 5% crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvent.