• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.45-53
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• 2002

The removal of chelated copper from anthraquinone dyes by cementation on powdered iron was studied. The removal of chelated copper was found to be a function of solution pH, amount of NTA and iron, and reaction temperature. In the presence of NTA, reaction rate of cementation was found to be strongly dependent on reaction temperature, solution pH, amount of NTA and amount of iron powder. These experimental results can be explained successfully by the distribution of complexed copper iron in solutions.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.626-631
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• 2006

The adsorption features of copper ion have been investigated by taking the barley residue which occurring from the beer production process as an adsorbent. Under the experimental conditions, adsorption equilibrium of copper ion was attained within 30 minutes after the adsorption started and the adsorption reaction was observed to be first order. As the temperature increased, the adsorbed amount of copper ion at equilibrium was also increased, which indicated that the adsorption reaction was endothermic. Based on the experimental results which obtained by varying the temperatures, several thermodynamic parameters for copper adsorption reaction were estimated. Regarding the electrokinetic behavior of barley residue, its electrokinetic potential was observed to be positive below pH 5 and turned into negative above this pH. In the pH range from 1.5 to 4, copper adsorption was found to be increased, which was well explained by the electrokinetic behavior of barley residue in the pH range. When nitrilotriacetic acid, which is a complexing agent, was coexisted with copper ion, equilibrium adsorption of copper ion was decreased and this was presumed to be due to the formation of metal complex. In addition, the adsorbed amount of copper ion was examined to be increased when $KNO_3$ was coexisted, however, it approached a saturated value above a certain concentration of $KNO_3$.

• Journal of Korean society of Dental Hygiene
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• v.10 no.3
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• pp.531-540
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• 2010

Objectives : In this study, following the cavity restorations with low copper conventional alloy, high copper admixed one and high copper unicompositional one, which are used the most frequently in a clinical setting at the present, to experiment the time-dependent changes of strength, bubbles were examined. Besides, to examine the detrimental effects of mercury contained in dental amalgam, the amount of mercury release was evaluated. Methods : As dental amalgams which were used herein, [BESTALOY], [Hi-Aristaloy 21] and [Sybraloy] were selected for a low-copper conventional amalgam, a high-copper admixed one and a high-copper unicompositional one in the corresponding order. The formation of bubbles and the weight ratio of mercury release were evaluated using a field emission scanning electron microscope (FE-SEM). Thus, the following results were obtained: Results : 1. The time-dependent amount of mercury release reached a statistical significance in three types of alloys, which was shown in such a descending order as [BESTALOY], [Hi-Aristaloy 21] and [Sybraloy]. 2. A low-copper conventional type, BESTALOY is a cutting type and it was found to have an increased formation of fine bubbles. In the remaining two types, [Hi-Aristaloy 21] (a high-copper admixed alloy) and [Sybraloy] (a high-copper unicompositional alloy), the time-dependent changes in the formation of bubbles was negligible. Conclusions : Accordingly, this type of mercury release from amalgam alloy denotes the difference in the weight ratio of total constituents between after 24 hours and after two weeks. But further studies are warranted to examine the amount of mercury release which is detrimental to human bodies. Besides, a low-copper conventional alloy is a cutting type and it was characterized by the abundant formation of bubbles in a time-dependent manner. This implies that the strength of amalgam is impaired, which should be considered in selecting the appropriate amalgam alloy in a clinical setting.

• Tribology and Lubricants
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• v.20 no.6
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• pp.299-305
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• 2004

The wear properties of clutch facing materials with two different copper amounts were evaluated against the fly-wheel materials used in clutch system, such as gray cast iron and spheroidal graphite cast iron. Sliding wear tests were carried out for four different combinations with these clutch facing materials and flywheel materials at different speeds and applied loads. Results showed that the clutch facing material contained a higher copper amount had the better wear resistance. And using the gray cast iron as the counter material, clutch facing material resulted in the much lower wear rate, regardless of the copper amount. It is obvious that the wear properties of clutch facing material are influenced from the thermal conductivities of the clutch facing material and the counter material.

• Resources Recycling
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• v.28 no.1
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• pp.62-72
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• 2019

Generally, $H_2SO_4$ and Cu metal are used as raw materials for producing copper sulfate. The study relates to a method for producing copper sulfate using electrowinning from a waste solution of copper chloride. Uses are used for copper plating for industry, plating, feed, agriculture, electronic grade PCB. Conventional methods for producing copper sulfate have a problem of a large amount of waste water and a high energy cost. A study on the production method of copper sulfate ($CuSO_4$), which is the most used among copper (Cu) compounds, has a low process operation ratio, a small amount of waste water, and a simple manufacturing process. It is easy to remove Na, Ca, Mg, and Al as impurities by using a cationic membrane. At the same time, high purity copper powder could be recovered by an electrowinninng method. Using the recovered copper powder, high purity copper sulfate could be produced.

• KSTLE International Journal
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• v.2 no.1
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• pp.22-28
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• 2001

A resin bonded copper-graphite brush was investigated to evaluate the characteristics electrical signal transmission through a sliding contact as a function of the relative amount of graphite and copper in the brush. Particular attention was given to the correlation between electrical signal fluctuation and tribological properties in an electrical sliding contact system. A ring-on-block type tribotester was used for this experiment and the ring was made from pure copper. Results showed that a copper-graphite brush at a particular composition range exhibited the most stable frictional behavior with a minimum voltage drop. The amount of voltage drop at the friction interface was affected by the surface roughness, transfer film formation at the friction interface, and the real area of contact. Microscopic observations and the surface analysis showed a good agreement with the results from this experiment. The results also indicated that the electrical signal flunctuation was directly associated with the oscillation of the coefficient of friction during sliding by nanoscale variation of contacts at the friction interface.

• Journal of Environmental Health Sciences
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• v.12 no.1
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• pp.47-54
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• 1986

The purpose of the study is to determine the effects of sodium alginate on the suppression of organ accumulation of heavy metals were tested by mice. The seventy mice were divided into the control group and the experimental groups. The mice of cadmium group were subdivided into three groups by dose of 10 ppm cadmium group, adding 1% sodium alginate to the diets contaminated with 10 ppm cadmium group and adding 10% sodium alginate to the diets contaminated with 10 ppm cadmium group. The mice of copper group were subdivided into three groups by dose of 10 ppm copper group, adding 1% sodium alginate to the diets contaminated with 10 ppm copper group, and adding 10% sodium alginate to the diets contaminated with 10 ppm copper group. After the series of feeding of twenty-one days, the mice were killed and examined. Organs and feces were removed and analyzed for cadmium and copper amounts. The results obtained were as follows 1. As for average body weight gains, those of control group mice were the highest than heavy metal group and those of adding 10% sodium alginate to the diets contaminated with 10 ppm copper group the lowest. 2. The amount of cadmium accumulated in liver and kidney was higher than blood. The amount of cadmium in organs was higher in cadmium group than adding sodium alginate to the diets contaminated with cadmium group. 3. The amount of copper in liver was the highest, and that of copper in blood was the lowest. 4. The excretion of heavy metals was promotioned by adding 10% sodium alginate to the diets contaminated with 10 ppm heavy metal. ( P < 0.05 ).

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.863-867
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• 2008

Pitch based activated carbon fiber(ACF) was prepared from reformed naphtha cracking bottom oil(NCB oil) by melt spinning. The fibers obtained were stabilized, carbonized, and then steam activated. The ACF was sensitized with Pd-Sn catalytic nuclei via a single-step activation approach. This sensitized ACF was used as precursors for obtaining copper plated ACFs via electroless plating. ACFs uniformly decorated with metal particles were obtained with reduced copper plating in the reaction solution. Effects of the amount of copper on characteristics of ACF/Cu catalysts were investigated through BET surface area, X-ray diffraction, scanning emission microscopy, and ICP. The amount of copper increased with plating time, but the surface area as well as the pore volume decreased. NO conversion increased with reaction temperature. NO conversion decreased with increasing the amount of copper, which is seemed to be due to the reduction of surface area as well as the dispersion of copper.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.2
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• pp.157-166
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• 1997

The biosorption performances of copper were investigated by the immobilized biomass of nonliving marine brown algae Undaria pinnatifida by each of the Ca-alginate method(Ca-ALG), Ba-alginate method(Ba-ALG), polyethylene glycol method(PEG), and carrageenan method (CARR). The copper removal performance increased but the copper uptake decreased as the biomass amount was increased. However, the copper uptake by the immobilized biomass increased with increasing initial copper concentration. Among the immobilization methods, the copper uptake decreased in the following sequence: Ca-ALG > Ba-ALG > PEG > CARR. The pattern of copper uptake by the immobilized biomass fitted the Langmuir isotherm better than the Freundlich isotherm. Desorption of deposited copper with 0.05 ~0.5M HCI, resulted in no changes of the copper uptake capacity of the immobilized biomass by the immobilization methods except for PEG, through five subsequent biosorption/desorption cycles. There was no damage to the immobilized biomass which retained its macroscopic appearance in repeated copper uptake/elution cycles.

• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.60-67
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• 2020

In this study, copper (II) oxide powder for electroplating was prepared by recovering CuCl₂ from NaClO₃ type etching wastes via recovered non-sintering two step chemical reaction. In case of alkali copper carbonate [mCuCo₃·nCu(OH)₂], first reaction product, CuCo₃ is produced more than Cu(OH)₂ when the reaction molar ratio of sodium carbonate is low, since m is larger than n. As the reaction molar ratio of sodium carbonate increased, m is larger than n and Cu(OH)₂ was produced more than CuCO₃. In the case of m has same values as n, the optimum reaction mole ratio was 1.44 at the reaction temperature of 80℃ based on the theoretical copper content of 57.5 wt. %. The optimum amount of sodium hydroxide was 120 g at 80℃ for production of copper (II) oxide prepared by using basic copper carbonate product of first reaction. At this time, the yield of copper (II) oxide was 96.6 wt.%. Also, the chloride ion concentration was 9.7 mg/L. The properties of produced copper (II) oxide such as mean particle size, dissolution time for sulfuric acid, and repose angle were 19.5 mm, 64 second, and 34.8°, respectively. As a result of the hole filling test, it was found that the copper oxide (II) prepared with 120 g of sodium hydroxide, the optimum amount of basic hydroxide for copper carbonate, has a hole filling of 11.0 mm, which satisfies the general hole filling management range of 15 mm or less.