• Resources Recycling
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• v.13 no.6
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• pp.37-42
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• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite sample with different content of NiO and ZnO. The power loss, Pcv decreases monotonically with increasing temperature and attains to a certain value at around 100~120 degrees Celsius. The frequency dependence of Pcv can be explained by Pcv~f$^n$, and n is independent of the frequency, f up to 1 MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss(Ph) and residual loss(Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while Pcv-Ph is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}_i$ like following equations could be formularized. ${\mu}_i{\mu}_0=I_s^2/(K_I+b{\sigma}_0{\lambda}_s)$ Wh=13.5(I$_s^2/{\mu}_i{\mu}_0)$ Where ${\mu}_0$ is permeability of vacuum, I$_s$ is saturation magnetization, K$_I$ is anisotropy constant, $s_0$ is internal heterogeneous stress, ${\lambda}_s$ is magnetostriction constant, b is unknown constant, and Wh is hysteresis loss per one cycle of excitation (Ph=Wh${\times}$f). Steinmetz constant of Ni-Cu-Zn ferrite, m=1.64~2.2 is smaller than that of Mn-Zn ferrites, which suggests the difference of loss mechanisms between these materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.85-90
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• 1993

In this survey the results showing the highest values among the analyzed data of all specimens are summarized as follow. At Kwangyang bay Cu in the fishery was detected up to 1.208ppm and the level of Cu and Pb in sediment of this area were 2.13 and 4.34ppm, respectively. The contents of Hg in fishery and sediment of Yeosu bay were 0.102 and 0.032ppm. The levels of Pb in fishery and seawater of Sunchon bay were 0.039ppm and 0.013$\mu\textrm{g}$/L, respectively. At Posung bay the contents of Cd were 0.277ppm, 0.09$\mu\textrm{g}$/L and 0.08ppm in the specimens of fishery, seawater and sediment, respectively. The analyzed data of all specimens at Keamundo were very low level or undetectable. Of the 6 fishery samples, Charybdis japonica showed the upper level of Hg, Cu, Zn, Mn as 0.092, 1.905, 6.64, and 46.34ppm, respectively. The contents of Pb and Cd in Batillus cornatus were 0.045 and 0.38ppm respectively and other fishery had low level of heavy metal. In this study the contents of heavy metals analyzed in all specimens showed nearly natural occurrence level which is under the legal limits.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2004.12a
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• pp.3-11
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• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite samples with different content of NiO and ZnO. The power loss, Pcv decreases monotonically wi increasing temperature and attains to a certain value at around $100\~120$ degrees Celsius. The frequency dependence of Pcv can be explained by $Pcv\~f^n$', and n is independent of the frequency, f up to 1MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss, Ph and residual loss, (Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while (Pcv-Ph) is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}^i$ following equations could be formularized. $${\mu}_i{\mu}o=I_x\;^2/(K_1+bs_ol_s)\;\;\;\;(1)$$ $Wh=13.5(I_s\;^2/{\mu}_i{\mu}_o)\;\;\;\;(2)$$ Were ${\mu}_o$ is permeability of vacuum, $I_s$ saturation magnetization, $K_1$ anisotropy constant, $S_o$ internal heterogeneous stress, $I_s$, magnetostriction constant, b unknown constant. Wh hysteresis loss per one cycle of excitation (Ph: Wh*f). Steinmetz constant of Ni-Cu-Zn ferrites, $m=1.64\~2.2$ is smaller than the one of Mn-Zn ferrites, which suggests the difference of loss mechanism between these materials.

• Journal of Korea Foundry Society
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• v.18 no.3
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• pp.240-245
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• 1998

In the view point of the environmental conservation and the energy reduction, the recycling of metal scrap is coming as one of the global subjects in the world. In this study, the movement of intermetallics with electromagnetic force in a melt of a scrap of Al-Si-Cu alloy (JIS ADC12), which was widely used in diecasting process, was investigated in order to eliminate the Fe element, which was usually accumulated in a scrap. In this study, we applied electromagnetic method to eliminate Fe element in ADC12 aluminum alloy scrap which contains 1.64wt.% Fe and the effects of electromagnetic force on the particle movement was visualized and confirmed by water modeling and experiment. As a result, the Fe intermetallic compounds are moved to the direction opposite to that of the electromagnetic force as the force applies, thus eliminated from the bulk metal. Therefore, the content of Fe in matrix decreased from 1.64wt.% to 0.45wt.%.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.561-568
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• 2019

Objectives: The most commonly detected heavy metals in rocks and soils, including Pb, Cd, Cu, Fe, Mn and As, are representative pollutants discharged from abandoned mines and have been listed as potential sources of contamination in drinking water. This study focused on increasing the removal efficiency of heavy metals from drinking water resources by surface modification of natural adsorbents to reduce potential health risks. Methods: Iron oxide coating and graft polymerization with zeolites and talc was conducted for bipolar surface modification to increase the combining capacity of heavy metals for their removal from water. The removal efficiency of heavy metals was measured before and after the surface modification. Results: The removal efficiency of Pb, Cu, and Cd by surface modified zeolite showed 100, 92, and 61.5%, respectively, increases compared to 64, 64, and 38% for non-modified zeolite. This implies that bipolar surface modified natural adsorbents have a good potential use in heavy metal removal. The more interesting finding is the removal increase for As, which has both cation and anion characteristics showing 27% removal efficiency where as non-modified zeolite showed only 2% removal. Conclusions: Zeolite is one of the most widely used adsorptive materials in water treatment processes and bipolar surface modification of zeolite increases its applicability in the removal of heavy metals, especially As.

• Korean Journal of Crystallography
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• v.6 no.1
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• pp.27-35
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• 1995

The crystal structure of 1-tert-butoxycarbonyl-4-[N-(tert-butoxycarbonyl)-N-(ethoxycarbonylmethyl)amino]-3-phenylsulfonylpyrrolidind [C24H36O8N2S] has been from single crystal x-ray diffraction study ; C24H36O8N2S triclinic, p1, a=11.363(8)Å, b=11.589(6)Å, c=11.013(10)Å,α=95.32(6)°,β=98.64(7)°,γ=79.57(5)°,V=1406.8(18)Å3, t=293K, Z=2, CuKα(λ=1.5418Å). The molecular structure was solved by diredt method and refined by full-matrix least squares to a final R=9.78% for 3621 unique observed [F≥4σ(F)] reflections and 703 paramenters.

• Journal of Fashion Business
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• v.23 no.1
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• pp.64-73
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• 2019

The objective of this study was to investigate dyeing characteristics of silk, cotton and rayon fabrics using dyeing solution extracted from different varieties of tea. Comparative results of CIE Lab values of 360 pieces of dyed fabrics were studied to quantify the effects of dye concentrations (100%, 150%, and 200%) and mordants (Fe, Cu, Sn, Al). In addition, the color difference values (${\Delta}E$) of the dyed and mordanted fabrics were evaluated. The results of the study were as follows: First, among all of the 360 pieces of silk, cotton and rayon fabrics, the best dyeing effects was observed on silk fabrics. Second, the dyeing effect of the eight different types of tealeaves belonging to green tea, oolong tea, black tea, and dark tea tended to enhance as the degree of fermentation increased. Third, when the fabrics were mordanted with Fe, Cu, Sn, Al mordants, various colors such as brown, brownish red, brownish yellow, gray, and reddish brown were obtained.

• Journal of Welding and Joining
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• v.13 no.4
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• pp.55-64
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• 1995

A study was made to examine the effects of postweld heat treatment(PWHT) on the toughness and microstructures in the weld heat affected zone(HAZ) of Cu-bearing HSLA-100 steel. The Gleeble thermal/mechanical simulator was used to simulate the weld HAZ. The details between toughness and PWHT of HAZ were studied by impact test, optical microscopy(O.M.), scanning electron microscopy (SEM), transmission electron microscopy(TEM) and differential scanning calorimetry(DSC). The decrease of HAZ toughness in single thermal cycle comparing to base plate is ascribed to the coarsed-grain formed by heating to 1350.deg.C. The increase of HAZ toughness in double thermal cycle comparine to single thermal cycle is due to the fine ferrite(.alpha.) grain transformed from austenite(.gamma.)formed by heating to .alpha./.gamma. two phase region. Cu precipitated during aging for increasing the strength of base metal is dissolved during single thermal cycle to 1350.deg.C and is precipitated little on cooling and heating during subsequent weld thermal cycle. It precipitates by introducing PWHT. Thus, the decrease of toughness in triple thermal cycle of $T_{p1}$ = 1350.deg.C, $T_{p2}$ = 800.deg.C and $T_{p3}$ = 500.deg.C does not occur owing to the precipitation of Cu. The behaviors of Cu=precipitates in HAZ is similar to that in base plate. PWHT at 550.deg.C shows highest hardness and lowest toughness, whereas PWHT at 650.deg.C shows reasonable toughness, which improves the toughness of as-welded state.state.

• Journal of Welding and Joining
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• v.24 no.2
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• pp.64-70
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• 2006

The 3-dimensional (3D) chip stacking technology is a leading technology to realize a high density and high performance system in package (SiP). There are several kinds of methods for chip stacking, but the stacking and interconnection through Cu filled through-hole via is considered to be one of the most advanced stacking technologies. Therefore, we studied the optimum process of through-hole via formation and Cu filling process for Si wafer stacking. Through-hole via was formed with DRIE (Deep Reactive ion Etching) and Cu filling was realized with the electroplating method. The optimized conditions for the via formation were RE coil power of 200 W, etch/passivation cycle time of 6.5 : 6 s and SF6 : C4F8 gas flow rate of 260 : 100 sccm. The reverse pulsed current of 1.5 A/dm2 was the most favorable condition for the Cu electroplating in the via. The Cu filled Si wafer was chemically and mechanically polished (CMP) for the following flip chip bumping technology.

• Nutritional Sciences
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• v.3 no.1
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• pp.42-46
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• 2000

The purpose of this study was to examine the intake of Cr, Cu, and Zn, which play important roles in lipid metabolism, and the relationship of these microminerals with serum lipids of healthy college living in the Choongnam area. The nutritional status of the subjects(35 women) was evaluated based on anthropometric measurements, 24-hr dietary recall for 3 days. Three-day meals and fasting blood were collected to analyze Cr, Cu, and Zn. The mean age, height, weight and BMI were 20 years, 158 cm, 55kg and 22.42kg/$m^2$ respectively. The mean daily energy intake was 85.9% of RDA for Koreans. The ratio of energy from carbohydrate, protein and fat was 60 : 24 : 16. The mean daily intake of Cr, Cu, and Zn was 60.07 $\mu\textrm{g}$/day, 2.64 mg/day, and 11.35 mg/day, respectively. The mean serum levels of Cr, Cu, and Zn were 143$\mu$g/dl, 81.34$\mu$g/dl, adn 101.54$\mu$g/dl, respectively. The mean serum levels of total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol were 158.56mg/dl, 29.27 mg/dl, 56.00mg/dl, 6.12mg/dl, respectively. In conclusion, the subjects of the present study were healthy and consumed normal levls of dietary Cr, Cu and Zn, which play roles in lipid metabolism. Therefore, serum lipids of the subjects were all in the normal range. There was no significant correlation between dietary microminerals and serum lipids.