• Journal of Plant Biology
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• v.23 no.2
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• pp.55-60
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• 1980

The quantity of heavy metals (As, Cd, Cu, Pb, Zn) contained in marine algae collected in Onsan-myon on the east coast of Korea from March to December 1978 was determined as a part of the environmental base line survey of the Onsan Industrial Base. In general, green algae have a higher Cu content than either brown or red algae, and brown algae have higher As and lower Cu contents, while red algae have a higher Zn content. Significant differences between algal species in either Cd or Pb content were however not found.

• Korean Journal of Environmental Agriculture
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• v.6 no.1
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• pp.25-30
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• 1987

This study was conducted to find out the effect of several improvers such as triple super phosphate, slaked lime, wollastonite and gypsum for reducing Cd content in brown rice. Several improvers were applied to two different types of soils which are contaminated with copper-zinc mine wasted and sludge.(Soil I contained Cd : 7.88, Cu : 57.9, Zn : 175.0 ppm, Soil II contained Cd : 3.95, Cu : 30.2, Zn :124.0 ppm) In general, effects of improvers on reducing content of Cd, Cu and Zn in brown rice were greater in soil I than soil II. In soil I, the Cd content of brown rice was reduced to 0.4ppm below by application of triple superphosphate, fused phosphate, slaked lime and gypsum, 98, 225, 190 and 276Kg/10a, respectively. Triple superphosphate was more effective than fused phosphate in reducing uptake of Cd, Cu and Zn by applying them as an equal amount of phosphorous, also to equal alkalinity, slaked lime had the highest effect. Negatively linear effect was found between soil pH and Cd and Zn content in brown rice. As to above results, it was no doubt that triple superphosphate, fused phosphate and slaked lime would be applied to reduced heavy metals in brown rice. The slaked lime, triple super phosphate and fused phosphate were available to reduce uptake of Cd, Cu and Zn by rice plant grown in the soil contaminated with mine waste and sludge.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.300-302
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• 1996

Using the AC and DC methods we have studied th electrical properties of ZnO added TiO$_2$. The electrical conductivity of ZnO added TiO$_2$ was nearly unchanged with increasing the content of ZnO. Ac conductivity and conductance as a function of Frequency showed the similar trends. The impedance, admittance, and modulus spectrums were consistent with the results of DC conductivity.

• Economic and Environmental Geology
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• v.28 no.3
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• pp.221-229
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• 1995

The heavy metal contents and their dispersion patterns in stream water, stream sediments, land plants and aquatic larvae collected from the hydrologic system flowing via the wasted ore dump of the Moak Au-Ag mine were investigated systematically in order to evaluate the environmental impacts of the abandoned metal mine. The heavy metal content increases abruptly in the vicinity of the wasted ore dump, then attenuated with increasing distance from the mine area. Attenuating rates were stream water > stream sediments > land plants > aquatic larvae. On the other hand, the cumulative content of heavy metals was stream sediments >aquatic larvae > land plants > stream water. Each element tends to be enriched selectively according to media; Zn > Cu > Cd > Pb in stream water, Zn > Pb > Cu > Cd in stream sediments and land plants, and Zn > Cu > Pb > Cd in aquatic larvae. These results show that the degree of enrichment and dispersion of pollutant extruded from the wasted ore dump are different according to elements and media, and that the circulation system of materials of each medium is different. The heavy metals, especially Cu, Pb and Zn, of polluted downstream sediments occur in high proportions of Fe-Mn oxides and organic bounded forms, which show high potential of a secondary pollution source. The content of heavy metals and their dispersion patterns in stream sediments are different from those of ten years ago; pollution levels of heavy metals were degraded in various ranges. The Zn and Cu-polluted areas were widened whereas Fe and Pb-polluted areas were reduced. In crops collected from the farm lands in downstream area, the pepper was more concentrated in all heavy metal than rice. The pepper showed some contaminated level in Cu(9.7ppm) and Zn(149ppm), and the rice in Zn(90ppm). However, both crops showed no significant level in Cd(<0.2ppm) and Pb(<0.5ppm).

• Journal of Nutrition and Health
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• v.24 no.2
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• pp.87-96
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• 1991

This study was undertaken to investigate the effect of the levels of dietary Zn and alcohol consumption on lipid metabolism in Sprague-Dawley male rats weighing 80 to 90g for eight weeks. Ninety rats were divided into nine groups according to Zn levels and alcohol consumption such as no alcohol group[low Zn diet group(<1ppm. LZ) control Zn diet group(30ppm. CZ) high Zn diet group(60ppm, HZ)] 10% alcohol consumption group[the same Zn levels as no alcohol group LZLA, CZLA, HZLA] 20% alcohol consumption group[the same Zn levels as no alcohol group, LZHA, CZHA, HZHA] The results obtained were summarized as following : 1) In the serum total cholesterol increased with increasing dietary Zn levels but decreased with alcohol consumption. HDL-cholesterol decreased with alcohol consumption. Triglyce-ride in alcohol group was higher than no alcohol group. In alcohol group triglyceride increased with decreasing dietary Zn levels. 2) In the liver total lipid in alcohol group was higher than no alcohol group HA group showed a significant increase. Triglyceride increased with alcohol consumption. 3) In the serum and liver Zn content increased with increasing dietary Zn levels but decreased with alcohol consumption.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.2
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• pp.164-169
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• 2013

The effect of co-sputtering condition on the structural properties of $Mg_xZn_{1-x}O$ thin films grown by RF magnetron co-sputtering system was investigated for manufacturing UV LED. $Mg_xZn_{1-x}O$ thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The $Mg_xZn_{1-x}O$ thin films have sufficient crystallinity on the high ZnO power. The EDS analyzed showed that the Mg content in the $Mg_xZn_{1-x}O$ films decreased from 3.99 to 24.27 at.% as the RF power of ZnO target increased. The Mg content in the $Mg_xZn_{1-x}O$ films could be controlled by co-sputtering power.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.46-50
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• 2017

The Zn1-xMnxO ($0.00{\leq}x{\leq}0.06$) samples have been synthesized in the form of powder by the coprecipitation method at low temperature using $Zn(CH_3COO)_2$. $2H_2O$ and $Mn(CH_3COO)_2$. $4H_2O$ powders, as well as HCl and $NH_4OH$ solutions as starting materials. Characterization was conducted using XRD, TEM, XRF, FTIR and VSM. The result shows that the $Zn_{(1-x)}Mn_xO$ ($0.00{\leq}x{\leq}0.06$) nanoparticles have the wurtzite phase with a hexagonal structure and particle sizes ranging from 17.48 to 118.83 nm. In a qualitative analysis of XRF, the peaks that confirm the existence of the manganese element in Mn-doped ZnO samples were observed. Meanwhile, FTIR test result shows that there are peaks at around $500cm^{-1}$ and $400cm^{-1}$ in the FTIR spectra for Mn doped ZnO samples which clearly reveal the existence of the (Zn, Mn)-O strain mode. The (Zn, Mn)-O absorption peak positions have shifted to a lower wave number with increasing Mn doping content. The peak intensity is also lower if compared to that of the ZnO sample without doping. From the VSM test, it is shown that $Zn_{(1-x)}Mn_xO$ ($0.00{\leq}x{\leq}0.06$) nanoparticles are all paramagnetic having monotonically increased susceptibility as increasing Mn content.

• Korean Journal of Materials Research
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• v.2 no.5
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• pp.360-365
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• 1992

Ga-doped polycrystalline ZnO films on glass substrates were prepared by sputtering the targets, which had been prepared by sintering discs consisting of ZnO powder and various amounts of G$a_2O_3$, to investigate the effects of gallium doping and sputtering conditions on electrical properties. Optimizing the RF power density, argon gas pressure and gallium content, transparent Ga-doped ZnO films with resistivity less than 1$0^{-3}$ohm-cm are obtained. Electron concentration of undoped and Ga-doped ZnO films are order of $10^{18}$, $10^{21}$/c$m^2$respectively. After heat treatment in air and $N_2atmosphere, $ the resistivity of Ga-doped ZnO films increases by about two orders of magnitude. The optical transmission is above 80% in the visible range and the optical band widens as the Ga content increases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.574-580
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• 1994

The effect of dietary zinc(Zn) levels on cadmium (Cd)-induced hepatotoxicity was studied in serum and liver of rats. Adult male Spraque-Dawley rats were fed on diets containing one of three levels of zinc carbonate(0, 56, $560\mu\textrm{g}/kg$ diet) and Cd-treated groups were administrated oral intubation with cadmium chloride 95.0 mg/kg of body weight) at the sametime once a week. Net weight gain (NWG), feed intake (FI) and feed effciiency ratio (FER) in Zn deficiency groups significantly decreased as compared to that of control and excessive groups. Cd oral intubation caused a decrease in NWG and FI but an increase in Zn deficiency group in FER. GSH-Px, GST and catalase activity showed significant decrease in Zn deficiency and Zn excessive group. LPO content in liver significantly increased in Zn deficiency group. Cd oral intubation increased the content of LPO in Zn deficiency group as compared to control. GSH content and GST activity of hepatic tissue significantly decreased in Zn deficiency and excessive group. The activity of AST and ALT in serum were markedly increased in Zn deficiency, Zn excessive and Cd-treated groups. LDH and ALP activities significantly increased in Cd-treated group while ALP activity decreased by Zn deficiency. It was observed that the livers of rats exposed to Cd and Zn excessive group showed a marked increase of hepatic enzyme as compare to only Cd-treated in rats.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.183-191
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• 1991

A study was conducted to determine the influence of soil chemical properties on the distribution and forms of cadmium (Cd), lead (Pb), copper(Cu) and Zinc(Zn) in paddy soils near zinc mines. A sequential extraction procedure was used to fractionate the heavy metals in soils into the designated from of water soluble, exchangeable, organically bound, oxide/carbonate, and sulfide/residual. The predominant form of Cd, Pb, Cu and Zn in the soils was found to be sulfide/residual form. Oxide/carbonate Cd and Pb and organically bound Cu were high, while exchangeable Pb and Cu were very low. Water soluble Cd, Pb and Cu were not detected in the soils. The percentages of the heavy metals content in exchangeable fractions were inversely correlated with those in sulfide/residual fractions in the soils. Exchangeable Cd and Zn and the oxide/carbonate Pb were shifting to the sulfide/residual form with soil depth and the chemical forms of Cu were not changed. Organically bound Cu was positively correlated with soil organic matter content but Cd, Pb and Zn were not. The percentages of Cd, Pb and Zn content in exchangeable forms decreased with soil pH, while those in oxide/carbonate and sulfide/residual forms increased with soil pH. The amounts of oxide/carbonate and sulfide/residual forms of pb were higher than those of Cd and Zn at same soil pH.