• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.155-155
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• 2009

The copper plating was deposited by pulse reverse current (PRC) method with additives. The all specimens were first immersted in 10% H2SO4 for 10 minutes, and then were rinsed with deionized water. The current densities of forward pulse were 400mA/$cm^2$, and those of reverse pulse were 1900mA/$cm^2$ and 100mA/$cm^2$. Results are compared for different additives for pulse plating conditions. When it added in Only CH4N2S (TU) or only C10H13NO3S (SVH), the effect of surface side growth of Cu was not different. But when it added in TU and SVH, surface side growth of Cu decreased. Polarization curves were measured from OCP to -0.7 V at a rate of 1mV/sec. Each specimen was observed under the PHENOM to see surface morphology.

• Korean Journal of Crystallography
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• v.11 no.4
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• pp.212-223
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• 2000

A stochiometric mix of CuInTe₂ polycrystal was prepared in a honizonatal furnace. To obtain the single crystal thin films, CuInTe₂ mixed crystal was deposited on throughly etched GaAs(100) by the HWE system. The source and substrate temperatures were 610℃ and 450℃ respectively, and the thickness of the deposited single crystal thin film was 2.4㎛. CuInTe₂ single crystal thin film was proved to be the optimal growth condition when the excition emission spectrum was the strongest at 1085.3 nm(1.1424 eV) of photoluminescence spectrum at 10 K, and also FWHM of Double Crystal X-ray Rocking Curve (DCRC) was the smallest, 129 arcsec. The Hall effect on this sample was measured by the method of Van der Pauw, and the carrier density and mobility dependent on temperature were 9.57x10/sup 22/ electron/㎥, 1.31x10/sup -2/㎡/V·s at 293 K, respectively. The ΔCr(Crystal field splitting) and the ΔSo (spin orbit coupling splitting( measured at f10K from the photocurrent peaks in the short wavelength of the CuInTe₂ single crystal thin film were about 0.1200 eV, 0.2833 eV respectively. From the PL spectra of CuInTe₂ single crystal thin film at 10 K, the free exciton (E/sub x/) was determined to be 1064.5 nm(1.1647 eV) and the donor-bound exciton(D/sup 0/, X) and acceptor-bound exciton (A/sup 0/, X) were determined to be 1085.3 nm(1.1424 eV) and 1096.8 nm(1.1304 eV0 respectively. And also, the donor-acciptor pair (DAP)P/sub 0/, DAP-replica P₁, DAP-replica P₂ and self-activated (SA) were determined to be 1131 nm (1.0962 eV), 1164 nm(1.0651 eV), 1191.1 nm(1.0340 eV) and 1618.1 nm (0.7662 eV), respectively.

• Archives of Metallurgy and Materials
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• v.65 no.4
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• pp.1303-1306
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• 2020

TiNi alloys have excellent shape memory properties and corrosion resistance as well as high biocompatibility. This study investigated the effects of copper addition on the phase transitions and electrochemical corrosion behaviors of Ti₅₀Ni_50-xCu_x alloys. TiNi, Ti₅₀Ni₄₇Cu₃, Ti₅₀Ni₄₄Cu₆, and Ti₅₀Ni₄₁Cu₉ alloys were prepared using vacuum arc remelting followed by 4 h homogenization at 950℃. Differential scanning calorimetry and X-ray diffraction analyses were conducted. The corrosion behaviors of the alloys were evaluated using potentiodynamic polarization test in Hank's balanced salt solution at a temperature of 36.5 ± 1℃. The TiNi alloy showed phase transitions from the cubic B2 phase to the monoclinic B19' phase when the alloy was thermally cycled. The addition of copper to the TiNi alloy played a major role in stabilizing the orthorhombic B19 phases during the phase transitions of Ti₅₀Ni_50-xCu_x alloys. The shifts in the corrosion potential toward the positive zone and the low corrosion current density were affected by the amount of Cu added. The corrosion resistance of the TiNi alloy increased with increasing copper content.

• 보존과학연구
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• s.27
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• pp.5-22
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• 2006

Mireuksa is a temple that was established in the Baekjea Period and continued around to the 16thcentury. The sites of the temple throughout diverse periods such as the United Shilla Period, KoryuPeriod, and Chosun Period including the one of the early temple in the late Baekjea Period were discovered. In those temple sites, there were lots of diverse artifacts discovered including artifacts in the Bronze Age. In this study, the compositions of four bronze bells excavated from Mireuksa site in Iksan were analyzed and the manufacturing technique of bronze bells was studied through the observation of microstructure. Also, the analytical cases of ancient bronze bells were collected and compared. Furthermore, the provenance study of the bronze bells site was attempted with the Pbisotope ratio. The results aim to offer crucial keys for discovering the aspect of society as well as information about the origin, development, and the route of propagation of ancient technologies. Bronze bell No. 1 showed an unexpected composition as Cu was found 98.5% in it. There were shown twins which were created by annealing and an even phase in the fine grains. It was also shown that bronze bell No. 2 and 4 had a high content of Pb although they showed a similar composition with general bronze bells in terms of Sn content. As shown in the analysis characteristics table of Korean bronze bell of this study, the ancient bronze bell used Pb of which content was limited to 2.12% in general, however, the results showed 15.5% and 13.2% respectively, which is an excessive amount. Asa result of analyzing inclusion in the microstructure of bronze bell No. 2, it was found that sulfide group mineral was used since there appeared S(14.55%). Also, it was proven that $CuFeS_2$ or$Cu_5FeS_4$ was used as a raw material because there was a small amount of Fe. As a result of analyzing inclusion of bronze bell No. 4, the bronze bell sample contained S(13.43%) and it is thought that sulfide group mineral was used, however, it had no Fe. Therefore, it is not connected to $CuFeS_2$ which is the main mineral of Korea. In addition, a strain line was shown with processing in bronze bell No. 2 and 4. As a result of provenance study of bronze bell No. 2 and 4 using the Pb isotope ratio, they or their raw materials are estimated to come from the southern China. Bronze bell No. 3 showed only Cu and Sn, and it is featured with a relatively low amount of Sn(6.63%). The microstructure has only phase, andintergranular corrosion was highly in progress.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.211-216
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• 2001

The growth of Selenastrum capricornutum in culture was investigated as a function of ionic copper concentrations to verify the toxicity and physiological variation. In a $Cu^{++}$ excess culture (E: $Cu^{++}$ of $130{\mu}g/l$), the growth rate (K)(0.32) was lower than that of the control culture (C: $Cu^{++}$ of $0.065{\mu}g/l$) (0.61) after 8 days and the exponential growth rate ($R_E$) was also found to be lower in culture E (1.1) than culture C (2.9). On the contrary, the K of S. capricornutum in trace $Cu^{++}$ culture ($T_1$ and $T_2$, 0.72) after 6 days tended to be more increased than culture C (0.68). From 8 to 14 days of culture, the amounts of chlorophyllls a and b were increased in culture C (chlorophyll a, $106->126{\mu}g/g$ dry wt; chlorophyll b, $158->208{\mu}g/g$ dry wt; chlorophyll b were decreased in culture E (chlorophyll a, $309->235{\mu}g/g$ dry wt; chlorophyll b, $405->352{\mu}g/g$ dry wt). The amounts of chlorophylls in ionic copper trace culture ($T_1$ and $T_2$) [(chl a/b) of $T_1$: $384/620\;{\mu}g/g$ dry wt; (chl a/b) of $T^2$:$320/467{\mu}g/g$ dry wt] were increased more than the culture C($260/387{\mu}g/g$ dry wt). Howeveer, when photosynthetic rates were normalized to the dry weight of algae, the control culture continued to showed higher values than the treated culture ($T_1$). An appropriate amount of ionic copper ($T_1:\;26\;{\mu}g/l$) stimulated the grwoth of S. capricornutum than the ionic copper content of $13\;{\mu}g/l$ ($T_2$), while the excess amount of ionic copper ($130\;{\mu}g/l$) resulted in the highest toxicity to the growth of S. capricornutum.

• Molecules and Cells
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• v.24 no.1
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• pp.69-75
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• 2007

Alzheimer's disease is a neurodegenerative disorder associated with progressive loss of cognitive function and memory. Amyloid beta peptide ($A{\beta}$) is the major component of senile plaques and is known to exert its cytotoxic effect mainly by producing $H_2O_2$. Vascular endothelial growth factor (VEGF) is elevated in the cerebrospinal fluid (CSF) and brain of AD patients, and $H_2O_2$ is one of the factors that induce VEGF. Therefore, we tested whether $A{\beta}$ might be responsible for the increased VEGF synthesis. We found that $A{\beta}$ induced the production of $H_2O_2$ in vitro. Comparison of the amount of $H_2O_2$ required to induce VEGF synthesis in HN33 cells and the amount of $H_2O_2$ produced by $10{\mu}M\;A{\beta}_{1-42}$ in vitro suggested that a toxic concentration of $A{\beta}$ might induce VEGF synthesis in these cells. However, toxic concentrations of $A{\beta}$ failed to induce VEGF synthesis in several cell systems. They also had no effect on antioxidant enzymes such as glutathione peroxidase, catalase, and peroxiredoxin in HN33 cells. $Cu^{2+}$, $Zn^{2+}$ and $Fe^{3+}$ are known to accumulate in the brains of AD patients and promote aggregation of $A{\beta}$, and $Cu^{2+}$ by itself induces synthesis of VEGF. However, there was no synergistic effect between $Cu^{2+}$ and $A{\beta}_{1-42}$ in the induction of VEGF synthesis and $Zn^{2+}$ and $Fe^{3+}$ also had no effect on the synthesis of VEGF, alone or in combination with $A{\beta}$.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.100-103
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• 2010

In this study, NO reduction behaviors of copper-loaded mesoporous molecular sieves (Cu/MCM-41) have been investigated. The Cu loading on MCM-41 surfaces was accomplished by a chemical reduction method with different Cu contents (5, 10, 20, and 40%). $N_2/77$ K adsorption isotherm characteristics, including the specific surface area and pore volume, were studied by BET's equation. NO reduction behaviors were confirmed by a gas chromatography. From the experimental results, the Cu loading amount on MCM-41 led to the increase of NO reduction efficiency in spite of decreasing the specific surface area of catalysts. This result indicates that highly ordered porous structure in the MCM-41 and the presence of active metal particles lead the synergistical NO reduction reactions due to the increase in adsorption energy of MCM-41 surfaces by the Cu particles.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.582-586
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• 2006

This experiment was conducted to investigate the dietary effect of garlic powder (GP) and copper (Cu) on laying performances and the cholesterol content and quality characteristics of eggs during storage in laying hens. A total of one hundred and eighty, 50-wk-old, Hy-Line Brown layers were divided into 6 groups with 3 replicates per group (10 layers per replicate) and fed one of six diets containing GP 0%, GP 1%, GP 3%, GP 5%, Cu 200 ppm, or GP 3%-Cu 200 ppm for 5 wks. There were no differences in the laying performances and feed intakes bertween treatments. Eggshell strength, eggshell thickness and yolk color were also not affected by feeding of GP and Cu. With increasing dietary GP, Haugh unit was linearly increased after 2 wk of storage (p<0.05). The levels of serum total cholesterol in hens fed diets containing GP or Cu were lower than that of the control (p<0.05), but high density lipoprotein-cholesterol was not influenced by dietary GP or Cu. The content of egg yolk cholesterol from hens fed diets containing GP or Cu was significantly decreased from that of the control, except for the GP 1% group. Based on the results of this experiment, the decrease of Haugh unit during storage was alleviated by feeding of GP. The feeding of GP or Cu alone and in combination altered the cholesterol fractions in serum and reduced the content of egg yolk cholesterol in laying hens.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.2
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• pp.68-72
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• 2004

Sm-doped YBCO high $T_c$ superconductor was directionally grown by zone melt growth process in air atmosphere. Cylindrical green rods of $(Sm/Y)_{1.8}Ba_{2.4}Cu_{3.4}O_{7-x}$[(Sm/Y)1.8] oxides were fabricated by cold isostatic pressing (CIP) method using rubber mold. Based on the variation of melting temperature and growth rate, the microstructure and superconducting properties were systematically measured by using optical micrographs, TEM and SQUID magnetometer. In this study optimum melting temperature and growth rate were $1085^{\circ}C$ and 3.5 mm/hr respectively. Nonsuperconducting $(Sm/Y)_2BaCuO_5$ inclusions of (Sm/Y)1.8 superconductor were uniformly distributed within the superconducting (Sm/Y) $Ba_2Cu_3O^{7-x}$ matrix. The directionally melt-textured (Sm/Y)1.8 superconductor showed an onset $T_c$ $\geq$ 90K and sharp superconducting transition.

• Journal of the Korean Ceramic Society
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• v.26 no.2
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• pp.221-227
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• 1989

To investigate the development and densification YBa2Cu3O7-x(1-2-3) superconducting phase, the 1-2-3 phase powders have been prepared by citrate and nitrate processes with changing calcination temperature. Nearly pure 1-2-3 phase peaks have been obtained by calcining the precursor in air at 90$0^{\circ}C$ for 2.5h in citrate process but at 95$0^{\circ}C$ for 2.5h in nitrate process. The sintering density of citrate derived sample calcined at 80$0^{\circ}C$ has been about 4% higher than that calcined at 90$0^{\circ}C$, although the compacting density has been lower at 80$0^{\circ}C$ calcination. This can be explained that the 1-2-3 phase particles formed at 80$0^{\circ}C$ have reactive sub-micron size which has good sinterbililty.