• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3642-3644
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• 2014

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.324-327
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• 1998

The mechanisms of Cu2+ adsorption onto goethite, hematite and kaolinite are different. Goethite and hematite showed a similar adsorption behavior (ionic-strength independent), but kaolinite gave somewhat different result (ionic-strength dependent). These experimenal results were successfully simulated using a surface complexation model, TLM, which defines the inner- or outer-sphere complex. The chemical nature of Cu2+ adsorption onto kaolinite was qualitatively identified by EPR spectroscopy.

• Bulletin of the Korean Chemical Society
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• 제5권3호
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• pp.108-112
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• 1984

Interactions between metal ions and chitosan in solution were studied by spectroscopic and viscometric measurements. $Cu^{++}$-chitosan complex exhibited an absorption band at 265 nm, whereas D-glucosamine complex showed one at 245 nm. The difference in ${\lambda}_{max}$ was attributed to the different amine to $Cu^{2+}$ ratios of the complexes, that is, 2 : 1 for chitosan and 1 : 1 for D-glucosamine. The molar absorptivities and binding constants of the complexes were evaluatatled. The binding of $Cu^{2+}$ to chitosan was cooperative near pH 5, and both intra- and intermolecular chelations depending on chitosan and $Cu^{2+}$concentrations were observed, The intermolecular chelation was stabilized by addition of salts. The cooperative intermolecular chelation of $Ni^{++}$ was also observed at pH 6.2. No significant binding of other divalent ions was observed. The reported high adsorption abilities of chitosan particles for these ions were attributed to the deposition of metal hydroxide aggregates in pores of chitosan particles rather than chelation to amine groups.

• 대한금속재료학회지
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• 제47권5호
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• pp.297-303
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• 2009

Solvent extraction experiments of cupric and cuprous chloride with Alamine336 have been performed from HCl solution. In order to identify the solvent extraction reaction, distribution diagram of cupric and cuprous species with HCl concentration was obtained by considering complex formation reaction and the activity coefficient of solutes with Pitzer equation. Analysis of the solvent extraction data by graphical method together with the distribution diagram of copper indicated that solvent extraction reaction of copper with Alamine336 depends on HCl concentration. In strong HCl solution of 3 and 5 M, ${CuCl_4}^{2-}$ and ${CuCl_3}^{2-}$ took part in the solvent extraction reaction as Cu(II) and Cu(I), respectively. When HCl concentration was 1 M, ${CuCl_2}^-$ was extracted into the organic phase in the case of Cu(I) while adduct formation between $Cu^{2+}$ and Alamine336 was responsible for the solvent extraction reaction of Cu(II).

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.304-309
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• 2001

With the development of electromagnetic communication technology and increased use of electromagnetic wave, the countermeasure of EMI(Electromagnetic Interference) becomes more important socially, and interest for the electromagnetic wave absorber has also increased. In this paper, we have studied characteristics of frequency dependency on complex permittivity and complex permeability according to the changes of composition rate and sintering temperature of NiCuZn ferrite also known as electromagnetic wave absorber and further looked into effect of electromagnetic wave absorption properties. From the measurement where the composition of Fe$_2$O$_3$ and ZnO of NiCuZn ferrite was fixed at 49 and 34 mol% respectively while composition of NiO and CuO has been varied at each test, we found out that initial permeability and permittivity were high and the absorbing ability of electromagnetic wave recorded best with loss tangent(${\mu}$r"/${\mu}$r′) displays more than 1 within the frequency band of 2MHz～9.5MHz when the composition ratio of NiO was ranged around 8.5～9.5 mol% and the sintering temperature was 1,080$^{\circ}C$.

• Journal of Magnetics
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• 제14권4호
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• pp.155-160
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• 2009

This study examined the effects of a decrease in thickness of magnetic alloy flakes on the electromagnetic wave absorption characteristics of nanocrystalline $Fe_{73.5}Cu_1Nb_3Si_{15.5}B_7$ (at.%) alloy flakes/polymer composite sheets available for a quasi-microwave band. The thickness of FeCuNbSiB alloy flakes decreased to 1-2 $\mu$m with increasing milling time up to 24 h, and the composite sheet including alloy flakes milled for 24 h exhibited considerably enhanced power loss properties in the GHz range compared to the sheets having non-milled alloy powders. Although a considerable increase in loss factor upon milling was observed in the narrow frequency range of 4-6 GHz, there was no correlation between the complex permeability and flake thickness. However, the complex permittivity increased with increasing milling time, and there was good agreement between the milling time and the frequency dependences of the complex permittivity and power loss.

• 한국분말재료학회지
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• 제8권4호
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• pp.245-252
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• 2001

Recent remarkable progress in the semiconductor industry has promoted smaller size of semiconductor chips and increased amounts of heat generation. So, the demand for a substrate material to meet both the characteristics of thermal expansion coefficient and heat radiation has been on the increase. Under such conditions, tungsten(W)-copper(Cu) has been proposed as materials to meet both of the above characteristics. In the present study, the W-10wt.%Cu powders were synthesised by the mixing and hydrogen reduction of the starting mixture materials such as W-Cu, $W-CuCl_2$and $WO_3-CuCl_2$ in order to obtain the full densification. The W-10wt.%Cu produced by hydrogen reduction showed the higher interparticle friction than the simple mixed W-10wt%Cu because of the W agglomerates. In the dilatometric analysis the W-10wt.%Cu prepared from the $W-CuCl_2$was largely shrank by heating up $1400^{\circ}C$ at the constant heating rate of $5^{\circ}C$/min. The possibility of application of metal injection molding (MIM) was also investigated for mass production of the complex shaped W-Cu parts in semiconductor devices. The relationship between the temperature of molding die and the pressure of injection molding was analyzed and the heating up stage of 120-$290^{\circ}C$ in the debinding process was controlled for the most suitable MIM condition.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권2호
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• pp.87-91
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• 2003

본 연구는 산업시설에서 배출되는 대기오염물질이 인접한 주거지역에 영향을 미칠 것으로 예상되는 시화공업단지 주변의 공단지역, 주거지역 및 녹지지역의 토양을 대상으로 As, Cd, Co, Cr, Cu, Hg, Ni, Pb 및 Zn 함량을 조사하였다. 토양 중 중금속 함량의 범위는 As 0.58~3.81, Cd ND~0.91, Co 0.15~6.33, Cr ND~1.86, Cu 0.14~110.27, Hg ND~l.17, Ni 0.04~10.59, Pb 1.16~86.48 및 Zn 1.83~212.65 mg/kg으로서 전 지역에서 토양환경보전법의 토양오염기준이나 식물독성 유발기준에 비하여 매우 낮은 값을 나타내었다. As 함량은 전 지역에 걸쳐 비슷하였으나, Cd와 Cr 함량은 공단지역이 주거지역이나 녹지지역보다 각각 약 10배 및 5배정도 높았으며, 주거지역과 녹지지역은 비슷한 경향이었다. Co, Cu, Hg, Ni, Pb 및 Zn 함량은 공단지역이 주거지역이나 녹지지역보다 약 2~3배정도 높았으며, 주거지역과 녹지지역은 비슷한 경향이었다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1495-1500
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• 2014

Two new complexes with 5-methyl-1-(pyridine-3-yl)-1H-1,2,3-triazole-4-carboxylic acid (Hmptc) ligand: [$Cd(mptc)_2(H_2O)_4$] (1) and $[Cu(mptc)_4{\cdot}2H_2O]_n$ (2) were prepared and their crystal structures were determined by single crystal X-ray diffraction analyses. In complex 1, the Cd(II) ions coordinates with the pyridyl nitogen atom from the Hmptc ligand, forming a mononuclear Cd(II) compound. Complex 2 exhibits a novel two-dimensional (2D) polymer in which four Hmptc ligands stabilize the Cu(II) atom. And the coordination involves one nitrogen atom of the triazole, one oxygen atom of the carboxylic acid and the pyridyl nitrogen atom. In addition, FT-IR and solid-state fluorescent emission spectroscopy of two compounds have been determined.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.840-842
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• 2007