• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.101-109
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• 2008

The adsorption characteristics of cationic metals such as copper, cadmium, and lead onto the amorphous aluminum oxide, AMA-L, which was mineralized from raw sanding powder at $550^{\circ}C$ were investigated. Additionally, surface complexation reaction of cationic heavy metals onto AMA-L was simulated with MINEQL + software employing a diffuse layer model. From the batch adsorption tests in a single element system, the adsorption affinity of each metal ion onto AMA-L was following order: lead > copper > cadmium. In a binary system composed with copper and cadmium, quite a similar adsorption affinity was observed in each metal ion compared to the single element system. When the surface complexation constants obtained in the single system were used in the prediction of experimental adsorption results, model predictions were well fitted with experimental results of both single and binary systems.

• Journal of the Korean Chemical Society
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• v.60 no.2
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• pp.131-136
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• 2016

Copper ion induced photoluminescence (PL) quenching dynamics and recovery of the PL by zinc ions were investigated for CdSe based nanocrystals. When copper ions were added, CdSe quantum dots showed fast and dramatically PL quenching whereas PL of CdSe nanorod gradually decreased. In the presence of zinc ions, the PL of CdSe/CdS (core/shell) nanocrystals that have quenched by copper ions was efficiently recovered. It showed that the PL intensity of nanocrystals increased by 50% in a solution containing 1 μM zinc ions. The PL intensity was increasing with increasing zinc ions, and could be described by Langmuir binding isotherm model. We showcase that the CdSe based nanocrystals can be used as fluorescence turn-on sensor.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2900-2904
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• 2013

We present the synthesis and characterization of DTPA-bis(histidylamide) (1a), DTPA-bis(aspartamide) (1b), and their gadolinium complexes of the type $[Gd(L)(H_2O)]$ (2a:L = 1a; 2b:L = 1b). Thermodynamic stabilities and $R_1$ relaxivities of 2a-b compare well with Omniscan$^{(R)}$, a well-known commercial, extracellular (ECF) MRI CA which adopts the DTPA-bis(amide) framework for the chelate: $R_1$ = 5.5 and 5.1 $mM^{-1}$ for 2a and 2b, respectively. Addition of the Cu(II) ion to a solution containing 2b triggers relaxivity enhancement to raise $R_1$ as high as 15.3 $mM^{-1}$, which corresponds to a 300% enhancement. Such an increase levels off at the concentration beyond two equiv. of Cu(II), suggesting the formation of a trimetallic ($Gd/Cu_2$) complex in situ. Such a relaxivity increase is almost negligible with Zn(II) and other endogenous ions such as Na(I), K(I), Mg(II), and Ca(II). In vivo MR images and the signal-to-noise ratio (SNR) obtained with an aqueous mixture of 2b and Cu(II) ion in an 1:2 ratio demonstrate the potentiality of 2 as a copper responsive MRI CA.

• Resources Recycling
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• v.31 no.5
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• pp.59-66
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• 2022

To investigate the rate-determining step of nickel, cobalt and copper electrowinning, experiments were conducted by varying the electrolyte temperature and agitation speed using a rotating disc electrode. Analyzing the rate-determining step by calculating the activation energy in the electrowinning process, it was found that nickel electrowinning is controlled by a mixed mechanism (partly by chemical reaction and partly by mass transport), cobalt is controlled by chemical reaction, and copper is controlled by mass transfer. Electrowinning of nickel, cobalt and copper was performed by varying the electrolyte temperature and agitation speed, and the comparison of the current efficiencies was used the determine the rate-determining step.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1669-1678
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• 2011

Six new binuclear copper(II) complexes have been prepared by template condensation of the dialdehydes 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-l,4,8,11-tetraazacyclotetradecane (PC-a) and 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-l,4,8,11-tetraazacyclotetradecane (PC-b) with appropriate aliphatic diamines, and copper(II) perchlorate. The structural features of the complexes have been confirmed by elemental analysis, IR, UV-vis and mass spectra etc. The electrochemical behavior of all the copper(II) complexes show two irreversible one electron reduction process. The room temperature magnetic moment studies depict the presence of an antiferromagnetic interaction in the binuclear complexes. The catechol oxidation and hydrolysis of 4-nitrophenylphosphate were carried out by using the complexes as catalyst. The antimicrobial screening data show good results. The binding of the complexes to calf thymus DNA (CT DNA) has been investigated with absorption and emission spectroscopy. The complex [$Cu_2L^{1a}$] displays significant cleavage property of circular plasmid pBR322 DNA in to linear form. Spectral, electrochemical, magnetic and catalytic studies support the distortion of the copper ion geometry that arises as the macrocyclic ring size increases.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.964-972
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• 2001

The kinetics of copper ion biosorption by Pseudomonas stutzeri cells immobilized in alginate was investigated. During the first few minutes of the metal uptake, the copper biosorption was rapid and then became progressively slower until an equilibium was rapid, and then became progressively slower until an equilibrium was reached. At a biomass concentration of 100g/l, the copper biosorption reaction reached approximately 90% of the equilibrium position within 30 min. A Freundich-type adsorption isotherm model was constructed based on kinetics with different amounts of biomass. When using this model, the experimental values only agreed well with the predicted values in a solution containing less than 200 mg/l Cu(II). Desorption of the bound copper ions was achieved using electrolytic solutions of HCl, $H_2SO_4$, EDTA, and NTA (0.1 or 0.5 M). Metal desorption with 0.1 M NTA allowed the reuse of the biosorbent for at least ten consecutive biosorption/desorption cycles, without an apparent decrease in its metal biosorption capability. A packed-bed column reactor of the immobilized biomass removed approximately 95% of the metal in the first 30 liter of wastewater [containing 100 mg/l Cu(II)] delivered at a rate of 20 L/day, and, thereafter, the rate gradually decreased.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3615-3620
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• 2013

Two novel copper(II) bromide complexes with pyridine containing Schiff base ligands, $Cu(pmed)Br_2$ and $Cu(pmed)Br_2$ where pmed = N'-((pyridin-2-yl)methylene)ethane-1,2-diamine (pmed) and dpmed = N,N-diethyl-N'-((pyridin-2-yl)methylene)ethane-1,2-diamine (dpmed) were synthesized and characterized using X-ray single crystal structure analysis, optical and magnetic susceptibility measurements. Crystal structural analysis of $Cu(pmed)Br_2$ showed that the copper(II) ion has a distorted square-pyramidal geometry with the trigonality index of ${\tau}=0.35$ and two intermolecular hydrogen bonds, which result in the formation of two dimensional networks in the ab plane. On the other hand, $Cu(pmed)Br_2$ displayed a near square-pyramidal geometry with the value of ${\tau}=0.06$. In both compounds, the NNN Schiff base and one Br atom occupy the basal plane, whereas the fifth apical position is occupied by the other Br atom at a greater Cu-Br apical distance. The reported complexes show $g_{\mid}$ > $g_{\perp}$ > 2.0023 with a $d_{x2-y2}$ ground state and a penta-coordinated square pyramidal geometry. Variable temperature magnetic susceptibility measurements showed that the developed copper(II) complexes follow the Curie-Weiss law, that is there are no magnetic interactions between the copper(II) ions since the Cu--Cu distance is too far for magnetic contact.

• Molecules and Cells
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• v.39 no.3
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• pp.195-203
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• 2016

Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions ($Cu^+$ and $Cu^{2+}$), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped $Cu_2O$ and CuO crystals were prepared to test the role of the two different ions, $Cu^+$ and $Cu^{2+}$, respectively. The $Cu_2O$ crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The $Cu_2O$ crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. $Cu_2O$ crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit $Cu_2O$-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of $Cu^+$ ions in the vascular system, where $Cu^+$ induces autophagy while $Cu^{2+}$ has no detected effect.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.276-280
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• 2010

Copper(Cu) as an interconnecting metal layer can replace aluminum (Al) in IC fabrication since Cu has low electrical resistivity, showing high immunity to electromigration compared to Al. However, it is very difficult for copper to be patterned by the dry etching processes. The chemical mechanical polishing (CMP) process has been introduced and widely used as the mainstream patterning technique for Cu in the fabrication of deep submicron integrated circuits in light of its capability to reduce surface roughness. But this process leaves a large amount of residues on the wafer surface, which must be removed by the post-CMP cleaning processes. Copper corrosion is one of the critical issues for the copper metallization process. Thus, in order to understand the copper corrosion problems in post-CMP cleaning solutions and study the effects of DC biases and post-CMP cleaning solution concentrations on the Cu film, a constant voltage was supplied at various concentrations, and then the output currents were measured and recorded with time. Most of the cases, the current was steadily decreased (i.e. resistance was increased by the oxidation). In the lowest concentration case only, the current was steadily increased with the scarce fluctuations. The higher the constant supplied DC voltage values, the higher the initial output current and the saturated current values. However the time to be taken for it to be saturated was almost the same for all the DC supplied voltage values. It was indicated that the oxide formation was not dependent on the supplied voltage values and 1 V was more than enough to form the oxide. With applied voltages lower than 3 V combined with any concentration, the perforation through the oxide film rarely took place due to the insufficient driving force (voltage) and the copper oxidation ceased. However, with the voltage higher than 3 V, the copper ions were started to diffuse out through the oxide film and thus made pores to be formed on the oxide surface, causing the current to increase and a part of the exposed copper film inside the pores gets back to be oxidized and the rest of it was remained without any further oxidation, causing the current back to decrease a little bit. With increasing the applied DC bias value, the shorter time to be taken for copper ions to be diffused out through the copper oxide film. From the discussions above, it could be concluded that the oxide film was formed and grown by the copper ion diffusion first and then the reaction with any oxidant in the post-CMP cleaning solution.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.550-551
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• 2013

Large-area RF-driven ion source is being developed at Germany for the heating and current drive of ITER plasmas. Negative hydrogen (deuterium) ion sources are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER and DEMO. RF ion sources for the production of positive hydrogen ions have been successfully developed at IPP (Max-Planck- Institute for Plasma Physics, Garching) for ASDEX-U and W7-AS neutral beam injection (NBI) systems. In recent, the first NBI system (NBI-1) has been developed successfully for the KSTAR. The first and second long-pulse ion sources (LPIS-1 and LPIS-2) of NBI-1 system consist of a magnetic bucket plasma generator with multi-pole cusp fields, filament heating structure, and a set of tetrode accelerators with circular apertures. There is a development plan of large-area RF ion source at KAERI to extract the positive ions, which can be used for the second NBI (NBI-2) system of KSTAR, and to extract the negative ions for future fusion devices such as ITER and K-DEMO. The large-area RF ion source consists of a driver region, including a helical antenna (6-turn copper tube with an outer diameter of 6 mm) and a discharge chamber (ceramic and/or quartz tubes with an inner diameter of 200 mm, a height of 150 mm, and a thickness of 8 mm), and an expansion region (magnetic bucket of prototype LPIS in the KAERI). RF power can be transferred up to 10 kW with a fixed frequency of 2 MHz through a matching circuit (auto- and manual-matching apparatus). Argon gas is commonly injected to the initial ignition of RF plasma discharge, and then hydrogen gas instead of argon gas is finally injected for the RF plasma sustainment. The uniformities of plasma density and electron temperature at the lowest area of expansion region (a distance of 300 mm from the driver region) are measured by using two electrostatic probes in the directions of short- and long-dimension of expansion region.