• Journal of Environmental Science International
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• v.7 no.5
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• pp.717-723
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• 1998

The concentrations and wet deposition flux into the sea of heavy metals of precipitation in Pusan area were measured and estimated. The samples were collected by polyethylene bottle(30ι) from January to November in 1996, and heavy metals were analyzed by atomic absorption spectrometer. The concentration order of heavy metals was Al ＞Fe ＞Zn ＞Pb ＞Mn ＞Cu ＞Ni ＞Cd ＞Co, and they were high at inland sites and low at coastal sites. The enrichment factors for some metals(Zn, Cu, Pb, Cd), based on crustal Al, were significantly greater than unity, and the order was Cd ＞ Pb ＞ Zn ＞ Cu. This evidence suggests Cd and Pb are derived predominantly from non-crustal sources. Al, Fe and Mn contents showed good correlation with each other. Therefore this enrichment factor indicates similar geochemical behavior of these elements. The annual wet depositional flux(mg/ $m^2$ /yr) from Pl site was as follows: Al(121.1). Fe,(177.2), Zn(12.9), Mn(6.19), Pb(14.4), Cu(0.64), Ni(1.03), Cd(1.02) and Co(1.01).

• Journal of Korea Foundry Society
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• v.28 no.1
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• pp.31-36
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• 2008

Ti-Ni-Cu alloys are very attractive shape memory alloys for applications as actuators because of a large transformation elongation and a small transformation hysteresis. Rapidly solidified Ti-Ni alloy ribbons have been known to have the shape memory effect and superelasticity superior to the alloy ingots fabricated by conventional casting. In this study, solidification structures and shape memory characteristics of $Ti-Ni_{30}-Cu_{20}$ alloy ribbons prepared by melt spinning were investigated by means of DSC and XRD. Operating parameters to fabricate the amorphous ribbons were the wheel velocity of 55 m/s and the melt spinning temperature of $1500^{\circ}C$. The crystallization temperature was measured to be $440^{\circ}C$. The crystallized ribbons exhibited very fine microstructure after annealing at $440^{\circ}C$ for 10 minutes and $460^{\circ}C$ for 5 minutes and was deformed up to about 6.8% and 6.23% in ductile manner, respectively. Stress-strain curve of the ribbon exhibited a flat stress-plateau at 64 MPa and this is associated with the stress-induced a B2-B19 martensitic transformation. During cycle deformation with the applied stress of 220 MPa, transformation hysteresis and elongation associated with the B2-B19 transformation were observed to be $4.3^{\circ}C$ and 3.6%.

• Korean Journal of Crystallography
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• v.11 no.3
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• pp.137-146
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• 2000

The stoichiometric mix of evaporating materials for he CuInS₂ single crystal thin films was prepared. To obtain the single crystal thin films, CuINS₂ mixed crystal was deposited on etched semi-insulator GaAs(100) substrate by the hot wall epitaxy(HWE) system. The source and substrate temperature were 640℃ and 430℃, respectively and the thickness of the single crystal thin films was 2 ㎛. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility deduced from Hall data are 9.64x10/sup 22//㎥ and 2.95x10/sup -2/ ㎡/V·s, respectively at 293 K. he optical energy gap was found to be 1.53 eV at room temperature. From the photocurrent spectrum obtained by illuminating perpendicular light on the c-axis of the thin film, we have found that the values of spin orbit coupling splitting ΔSo and the crystal field splitting ΔCr were 0.0211 eV and 0.0045 eV at 10K, respectively. From PL peaks measured at 10K, were can assign the 807.7 nm (1.5350 eV) peak to E/sub x/ peak of the free exciton emission, the 810.3 nm(1.5301 eV) peak to I₂ peak of donar-bound exciton emission and the 815.6 nm(1.5201 eV) peak to I₁ peak of acceptor-bound excition emission. In addition, the peak observed at 862.0 nm(1.4383 eV) was analyzed to be PL peak due to donor-acceptor pair(DAP).

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.247-251
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• 2000

This study was conducted to investigate tissue nutrient contents and salt accumulation in plastic house soils cultivating lily, rose and carnation. The soil tested had high total salts, available phosphate and exchangeable potassium. The soil cultivating rose had highest salt concentvation followed by chose of carnation and lily. Tissue nutrient contents of lily were higher than chose of carnation and rose. In comparison among cultivars, the nutrient contents were as follows; 'Snow Qeen'>'Le Reve'>'Casa Blanca' in lily; 'Marina'>'Super star'>'Mary Devor'>'Madelon' in carnation; and 'Cocktail'> 'Marina'>'Maderon' in rose. The range of the nutrient contents were: T-N: $1.66\;{\sim}2.35%$, K: $1.73{\sim}2.23%$, Zn: $2.13{\sim}6.43\;mg/kg$, Cu: $3.79{\sim}13.89\;mg/kg$ in carnation; T-N: $0.79{\sim}1.65%$, P: $0.18{\sim}0.44%$, Ca: $0.59{\sim}1.26%$, Mg: $0.21{\sim}0.46%$, Zn: $23.65{\sim}90.30\;mg/kg$, Cu: $0.99{\sim}4.62\;mg/kg$ in lily; and T-N: $0.75{\sim}1.62%$, P: $0.17{\sim}0.30%$, K: $1.60{\sim}2.91%$, Ca: $0.64{\sim}0.94%$, Zn: $24.57{\sim}48.31\;mg/kg$, Cu: $3.10{\sim}9.08\;mg/kg$ in rose. The amount of nutrients uptake per plant was high in order of: K > T-N > Ca > Mg in lily; and T-N > K > Ca > P > Mg in rose.

• 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.