• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.240-242
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• 2011

A large scale and commercially feasible synthesis of 5-chloroindole and its 3-substituted analogues has been described via a halogen - halogen exchange reaction from 5-bromoindole and its derivatives using cuprous chloride and dipolar aprotic solvent N-methyl-2-pyrrolidone in one pot with good yields.

• Journal of the Korean Society for Railway
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• v.4 no.2
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• pp.62-70
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• 2001

Pure copper, Cu-1.1wt%Cd and ACSR(Aluminum Conductor Steel Reinforced) have been used as catenary materials of the electric railway system. Since these materials may be exposed to the corrosive environments like polluted air, acid rain and sea water, it is important to investigate the corrosion rates in various corrosive environments. The aqueous corrosion characteristics of catenary materials in aerated acid, neutral and alkali solutions were studied by using immersion corrosion tests, electrochemical measurements and analytical techniques. In order to examine corrosion characteristics according to the dissolved oxygen content, pH, chloride ion concentration ion, and the addition of Cd to Cu, a series of tests such as potentiodynamic polarization, a.c impedance spectroscopy and galvanic corrosion tests were carried out with these materials. Results showed that the addition of Cd to Cu and chloride ion in the solution have an adverse effects on the resistance to corrosion. Additionally, Galvanic currents between Al and steel wires of ACSR were confirmed by using ZRA(zero resistance ammeter) method.

• Corrosion Science and Technology
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• v.3 no.3
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• pp.118-126
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• 2004

The correlation between sensor output and corrosion rate of reinforcing steel was evaluated by laboratory electrochemical tests in saturated $Ca(OH)_2$ with 3.5 wt.% NaCl and confirmed in concrete environment. In this paper, two types of electrochemical probes were developed: galvanic cells containing of steel/copper and steel/stainless steel couples. Potentiodynamic test, weight loss measurement, monitoring of open-circuit potential, linear polarization resistance (LPR) measurement and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of steel bar embedded in concrete. Also, galvanic current measurements were conducted to obtain the charge of sensor embedded in concrete. In this study, steel/copper and steel/stainless steel sensors showed a good correlation in simulated concrete solution between sensor output and corrosion rate of steel bar. However, there was no linear relationship between steel/stainless steel sensor output and corrosion rate of steel bar in concrete environment due to the low galvanic current output. Thus, steel/copper sensor is a reliable corrosion monitoring sensor system which can detect corrosion rate of reinforcing steel in concrete structures.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.431-439
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• 2006

This research was conducted using a model home plumbing system composed of copper, stainless steel, galvanized iron, carbon steel, and PVC (polyvinyl chloride) pipe. The number of bacteria present in stainless steel pipe and PVC was higher than other pipes. High turbidity and zinc release were found in galvanized iron pipe material and detected during the first 6 months. Conversely, there was a decrease in turbidity and zinc release after 6 months resulting in levels similar to other pipes. Copper concentration decreased as operation times increased. In this experiment, the number of bacteria detected in biofilm for a copper pipe continued to increase. Pipe material influenced bacterial numbers in biofilm and water. This showed that elevated chlorine could not control bacterial growth in biofilm for galvanized iron and stainless steel systems. It also suggested that the dosing of chlorine might not be available for all kinds of pipes. Therefore, another complementary method should be introduced to manage biofilm effectively in water distribution systems.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.882-886
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• 2005

Copper(II) ion-selective PVC membrane electrode based on 2-mercaptobenzoxazole as a new ionophore and o-nitrophenyl octyl ether (o-NPOE) as plasticizer is proposed. This electrode revealed good selectivity for $Cu^{2+}$ over a wide variety of other metal ions. Effects of experimental parameters such as membrane composition, nature and amount of plasticizer, and concentration of internal solution on the potential response of $Cu^{2+}$ sensor were investigated. The electrode exhibits good response for $Cu^{2+}$ in a wide linear range of 5.0 ${\times}$ 10−.6-1.6 ${\times}$ $10^{-2}$ mol/L with a slope of 29.2 ${\pm}$ 2.0 mV/decade. The response time of the sensor is less than 10 s, and the detection limit is 2.0 ${\times}$ $10^{-6}$ mol/L. The electrode response was stable in pH range of 4-6. The lifetime of the electrode was about 2 months. The electrode revealed comparatively good selectivities with respect to many alkali, alkaline earth, and transition metal ions.

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.959-968
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• 2000

Direct reaction of elemental silicon with a mixture of (dichloromethyl)silanes 1 $[Cl_3-nMenSiCHCl_2:$ n = 0 (a), n = 1(b), n = 2(c), n = 3(d)] and hydrogen chloride has been studied in the presence of copper catalyst using a stirred bed reactor equ ipped with a spiral band agitator at various temperatures from $240^{\circ}C$ to $340^{\circ}C.$ Tris(si-lyl) methanes with Si-H bonds, 3a-d $[Cl_3-nMenSiCH(SiHCl_2)_2]$, and 4a-d $[Cl_3-nMenSiCH(SiHCl_2)(SiCl_3)]$, were obtained as the major products and tris(silyl)methanes having no Si-H bond, 5a-d $[Cl_3-nMenSiCH(SiCl_3)_2]$, as the minor product along with byproducts of bis(chlorosilyl)methanes, derived from the reaction of silicon with chloromethylsilane formed by the decomposition of 1. In addition to those products, trichlorosilane and tetra-chlorosilane were produced by the reaction of elemental silicon with hydrogen chloride. The decomposition of 1 was suppressed and the production of polymeric carbosilanes reduced by adding hydrogen chloride to 1. Cad-mium was a good promoter for and the optimum temperature for this direct synthesis was $280^{\circ}C$.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.1007-1013
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• 2004

This experiment was conducted to investigate the effect of cadmium levels on weight gain, nutrient digestibility and the retention of iron, copper and zinc in tissues of growing pigs. A total of one hundred and ninety-two crossbred pigs (barrows, Duroc$\times$Landrace$\times$Yorkshine, 27.67$\pm$1.33 kg of average initial body weight) were randomly allotted to four treatments. Each treatment had three replicates with 16 pigs per pen. The corn-soybean basal diets were supplemented with 0, 0.5, 5.0, 10.0 mg/kg cadmium respectively, and the feeding experiment lasted for eight-three days. Cadmium chloride was used as cadmium source. The results showed that pigs fed the diet containing 10.0 mg/kg cadmium had lower ADG and FCR than any other treatments (p<0.05). Apparent digestibility of protein in 10.0 mg/kg cadmium-treated group was lower than that of other groups (p<0.05). There was lower iron retention in some tissues of 5.0 mg/kg and 10.0 mg/kg cadmium treatments (p<0.05). However, pigs fed the diet 10.0 mg/kg cadmium had higher copper content in most tissues than that of any other groups (p<0.05). There was a significantly increase of zinc retention in kidney of 10.0 mg/kg cadmium additional group (p<0.05) and zinc concentrations in lymphaden, pancreas and heart of 10.0 mg/kg cadmium treatment were lower than those of the control (p<0.05). This study indicated that relatively high cadmium level (10.0 mg/kg) could decrease pig growth performance and change the retention of iron, copper and zinc in most tissues during extended cadmium exposure period.

• Korean Journal of Materials Research
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• v.22 no.7
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• pp.335-341
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• 2012

Recently, the demand for the miniaturization of printed circuit boards has been increasing, as electronic devices have been sharply downsized. Conventional multi-layered PCBs are limited in terms their use with higher packaging densities. Therefore, a build-up process has been adopted as a new multi-layered PCB manufacturing process. In this process, via-holes are used to connect each conductive layer. After the connection of the interlayers created by electro copper plating, the via-holes are filled with a conductive paste. In this study, a desmear treatment, electroless plating and electroplating were carried out to investigate the optimum processing conditions for Cu via filling on a PCB. The desmear treatment involved swelling, etching, reduction, and an acid dip. A seed layer was formed on the via surface by electroless Cu plating. For Cu via filling, the electroplating of Cu from an acid sulfate bath containing typical additives such as PEG(polyethylene glycol), chloride ions, bis-(3-sodiumsulfopropyl disulfide) (SPS), and Janus Green B(JGB) was carried out. The desmear treatment clearly removes laser drilling residue and improves the surface roughness, which is necessary to ensure good adhesion of the Cu. A homogeneous and thick Cu seed layer was deposited on the samples after the desmear treatment. The 2,2'-Dipyridyl additive significantly improves the seed layer quality. SPS, PEG, and JGB additives are necessary to ensure defect-free bottom-up super filling.

• Journal of Surface Science and Engineering
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• v.57 no.4
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• pp.274-284
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• 2024

In this study, copper foil was electroplated under high current density conditions. We used Polyethylene Glycol (PEG), known for its thermal stability and low decomposition rate, as an inhibitor to form a stable and smooth copper layer on the titanium cathode. The electrolyte was composed of 50 g/L CuSO₄ and 100 g/L H₂SO₄, MPSA as an accelerator, JGB as a leveler, and PEG as a suppressor, and HCl was added as chloride ions for improving plating efficiency. The copper foil electroplated in the electrolyte added PEG which induced to inhibit the growth of rough crystals. As a result, the surface roughness value was reduced, and a uniform surface was formed over a large area. Moreover, the addition of PEG led to priority growth to the (111) plane and the formation of polygonal crystals through horizontal and vertical growth of crystals onto the cathode. In addition, the grains became fine when more than 30 ppm of PEG was added. As the microcrystalline structure changed, mechanical and electrical properties were altered. With the addition of PEG, the tensile strength increased due to grain refinement, and the elongation was improved due to the uniform surface. However, as the amount of PEG added increased, the corrosion rate and resistivity increased due to grain refinement. Finally, it was possible to manufacture a copper foil with excellent electrical and mechanical properties and the best surface properties when electroplating was carried out under the condition of additives with Cl-20 ppm, MPSA 10 ppm, JGB 5 ppm, and PEG 10 ppm.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.625-628
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• 2012

We investigated the interaction between polyynes (linear carbon chains) and various metal nanoparticles (Ag, Au, and Cu) to provide insight into the optical properties of metal-polyynes systems prepared by different experimental techniques. Polyynes were produced by laser ablation in deionized water, metal nanoparticles solutions, and copper chloride solution. Metal nanoparticles complexes with polyynes were analyzed by Raman, surface-enhanced Raman scattering, and UV-vis spectroscopy.