• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.121-131
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• 1990

Four crop plants, such as green onion(Allium ascalonicum L.), radish(Raphanus sativus L.), potato(Solanum tubersum L.) and chinese cabbage(Brassica pekinensis Rupr), were grown in greenhouses to determine the accumulations of Cd and Zn absorbed by the plants grown on soils treated with municipal sewage sludge of different levels of 0, 22.5, 45.0 and 90.0 ton $ha^{-1}$ as soil dry weight. The result was analyzed to be comparable to the heavy metal content in the plant tissues among the crop species and the statistical characteristics were investigated to determin a possible relationship between causes of increased contents of Cd and Zn in plants and in soils. The results were as follows : 1. The Cd and Zn content in experimental crop plants increased with increase in quantity of treatment sludge. 2. The Cd and Zn content in roots of all experimental plants increased with sludge treatment amount in soil, in the following order : green onion>potato>chinese cabbage>radish. 3. The Cd content in leaves of crop plants were high in this order : green onion>radish>potato>chinese cabbage, and the Zn content in leaves of crop plants was high in this order. : potato>radish>chinese cabbage>green onion. 4. Concentrations of Cd in potato tubers, radish roots and chinese cabbage leaves ranged from 0.03 to 0.12 ppm. 5. Concentrations of Cd and Zn in plant tissues grown in sludge treated soil of 90.0 ton $ha^{-1}$ were 1.2 to 10 times and 0.4 to 2.3 times higher as compared with those absorbed from sludge-free soil, respectively. 6. The accumulation rates of Cd and Zn in sludge-treated plant tissue were almost constant except for green onion roots.

• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.161-171
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• 2019

Four-week-old male Korean native chicks (KNC) were assigned to 3 groups with 6 replicates (8 birds/replicate) in each group: a basal diet (CON, 100 ppm of Zn), basal diet fortified with 50 ppm of Zn with zinc oxide (ZnO), or basal diet fortified with 50 ppm of Zn with Zn-methionine (ZnM). Immediately after a 4-week-feeding trial, 6 birds per group were used to evaluate the effects of zinc supplements on antioxidant indicators and the mRNA expression of zinc transport genes. The nitrogen components, lipid peroxidation, and total antioxidant status in blood were not influenced by Zn fortified diets. However, the ZnM group showed a significant (P<0.05) increase in uric acid levels than those in the ZnO group. In the small intestine, superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities, and malondialdehyde (MDA) level were unaffected by zinc supplements. The activity of glutathione S-transferase (GST) was significantly (P<0.05) enhanced by Zn-methionine supplementation. In the liver, the activity of GST was significantly (P<0.05) increased by Zn-methionine supplement without affecting SOD, GPX, and MDA levels. With respect to the mRNA expression of zinc transport genes, the ZnM group displayed a strong tendency for increases in intestinal ZnT-1 (P=0.09) and ZnT-5 (P=0.06) levels, compared to those in the CON group. Moreover, the ZnM group showed a tendency (P=0.10) for up-regulation of hepatic metallothionein mRNA as compared with the CON group. In conclusion, the Zn-fortified diet with 50 ppm of Zn-methionine helped to improve GST activity and Zn transport gene expression in the small intestine or liver of KNC.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.135-145
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• 1992

This study was carried out to find out some characteristic responses of biological samples under the exposure of trace metals with the considering of Sex, age, residence period and smoking. Blood, Urine and Hair were collected from 116 dwellers in the vicinity of a smelting factory. Cd, Cu, Pb and Zn concentrations were determined by flame atomic absorption spectrophotometry and the following results were found important. 1) The concentrations of trace metals in the blood were 0.010+ 0.003 $\mu$g/ml in Cd, 0.82+ 0.11 $\mu$g/ml in Cu, 0.23_+ 0.13 $\mu$g/ml in Pb and 5.78_+ 1.43 $\mu$g/ml in Zn, those in the urine were 1.7_+ 1.7 $\mu$g/l in Cd, 16.5_+ 16.0 $\mu$g/l in Cu, 24.6_+ 23.0 $\mu$g/l in Pb and 367.7_+ 283.4 $\mu$g/l in Zn, and those in the hair were 0.52_+ 0.56 $\mu$g/g in Cd, 11.00_+4.01 $\mu$g/g in Cu, 8.53_+ 7.05 $\mu$g/g in Pb and 383.23_+ 110.56 $\mu$g/g in Zn. 2) In sex, the concentrations of Zn in the blood and urine of male were higher than those of female, however, the concentrations of Cd and Zn in the hair of female were higher than those of male. 3) The concentrations of Cd, Pb and Zn in the urine showed an increasing trend by age. 4) While the concentration of Cd in the urine increased, the concentration of Pb in the hair decreased by residential period in all the samples. 5) The concentrations of Cd and Zn in the blood and that of Zn in the urine of smoking group were higher than those of non-smoking group. The concentration of Pb in the blood of smoking group and those of Cd, Pb and Zn in the urine of non-smoking group showed increasing the trend by age. The concentrations of Cd and Zn in the urine of non-smoking group, the concentration of Zn in the hair of smoking group showed increasing trend by residential period, however, the concentrations of Pb in the blood and hair and that of Zn in the hair showed decreasing trend by residential period. 6) When the correlations of the concentrations between Zn (main smelting metal) and other metals were analyzed, Zn in the blood was significantly correlated with Cu, Pb and Zn in the urine (positively) and Zn in the urine was significantly correlated with Zn in the blood, Cd, Cu and Pb in the urine, and Pb in the hair (positively). Zn in the hair was significantly correlated with Cd in the urine and Cu in the hair (positively). 7) Consequently, it was useful to note that samples of urine showed higher sensitivity under the metal exposure than those of blood and hair in individual sampling. In addition, as trace metals showed higher accumulation in the hair of the groups, sampling of hair was more highly recommended than those of urine and blood in group sampling.

• Proceedings of the Optical Society of Korea Conference
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• 2001.08a
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• pp.254-255
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• 2001

No Abstract.See Full-text

• Korean Journal of Materials Research
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• v.7 no.4
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• pp.354-360
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• 1997

페르브스카이트 구조를 갖는 CaTiO$_{3}$-La(Zn$_{1}$2/Ti$_{1}$2)O$_{3}$계에서 소결 온도와 소결 시간의 증가에 따른 ZnO의 휘발과 이에 따른 고주파 유전 특성에 대하여 조사하였다. 시편 내부를 WDS 분석한 결과 위치에 따른 ZnO의 농도차를 관찰할 수 있었고, 시편의 두께를 달리하여 Qxf$_{o}$ 값을 조사한 결과 ZnO가 많이 휘발된 가장자리에서 더 높은 Qxf$_{o}$ 값을 얻을 수 있었다. 0.535CaTiO$_{3}$-0. 465La(Zn$_{1}$2/Ti$_{1}$2/)O$_{3}$몰비로 155$0^{\circ}C$, 2시간동안 합성한 결과 소결 밀도 5.31g/㎤, 유전율 50, Qxf$_{0}$34,000, 온도계수 +8ppm/$^{\circ}C$의 고주파 유전 특성을 갖는 소결체를 얻을 수 있었다.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.458-464
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• 1998

Variations of reaction sequence of $Pb(Zn_{0.6}Mg_{0.4})_{1/3}Nb_{2/3}O_3$[PZMN] with precusor mixing methods were ex-amined using X-ray diffraction and dielectric characteristics. In the present study three different types of precursor mixing methods (oxide mixing PbO+$ZnNb_2O_6+MgNb_2O_6$[Zn+MN] and PbO+(Zn,Mg)$Nb_2O_6$[ZMN] precursor mixing) were adopted. When the oxide mixing method was used for the PZMN synthesis a Zn-rich perovskite phase and pyrochlore phase were formed. Compared with PbO+ZN+MN precursor mixing method the PbO-ZMN precursor led to a lowering of the formation temperature for perovskite sin-gle phase. These variation of composition and formation temperature of the perovskite phase were dis-cussed in terms of the difference in the solid-reaction requence between these three different types of pre-cursor mixing.

• Journal of the Korean Ceramic Society
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• v.13 no.4
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• pp.5-8
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• 1976

Both oriented and non-oriented ferroxplana $Co_{1-x}Zn_xZ(Ba_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41})$ with x=0.00, 0.45 were prepared by conventional ceramic method. The magnetostrictions of thus prepared specimens were measured by use of the three terminal capacitor device at room temperature. The magnitude of measured values was approximately five times greater than that of ZnY ferroxplana. The easy-magnetization plane at room temperature of both CoZ and Co0.55 $Zn_{0.45}$Z was their basal plane. The magentostrictions in the basal plane and the other planes showed saturated values at magnetic field intensity of about 2Koe and 4Koe, respectively. The magnetostriction constants $K_1, \; K_2, \;K_3\; and\; K_4$ for CoZ were -2.4, -10.5, -5.9 and -45.2$\times10^{-6}$ , while those for $Co_{0.55}Zn_{0.45}Z$ were +0.1, -1.2, -6.3 and -39.0$\times$10^{-6}, , respectively.

• Journal of Korea Foundry Society
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• v.36 no.4
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• pp.117-125
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• 2016

The effects of the Zn content on the microstructure and corrosion behavior in 1M NaCl solution were investigated in Mg-(0~6)%Zn casting alloys. The MgZn phase was scarcely observed in the Mg-1%Zn alloy, while the Mg-(2~6)%Zn alloy consisted of ${\alpha}$-(Mg) and MgZn phases. With an increase in the Zn content, the amount of the MgZn phase was gradually increased. Immersion and electrochemical corrosion tests indicated that the Mg-1%Zn alloy had the lowest corrosion rate among the alloys, and a further increase in the Zn content resulted in the deterioration of the corrosion resistance. Microstructural examinations of the corroded surfaces and EIS analyses of surface corrosion films revealed that the best corrosion resistance at 1%Zn was associated with the absence of MgZn phase particles in the microstructure and the contribution of Zn element to the formation of a protective film on the surface. A micro-galvanic effect by the MgZn particles led to the increased rate of corrosion at a higher Zn content.

• Journal of the Korean Ceramic Society
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• v.40 no.1
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• pp.31-36
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• 2003

In this study, nano-sized NiCuZn-ferrites for the multi-layered chip inductor application were prepared by a coprecipitation method and its electromagnetic properties were analyzed. Also, the property of low temperature sintering were studied with the initial heat treatment of powder.$(Ni_{0.4-x}Cu_xZn_{0.60})_{1+w}(Fe_2O_4)_{1-w}$ (x=0.2, w=0.03) were calcined at $300^{circ}C~750^{circ}C.$ The sintered NiCuZn-ferrites at $900^{\circ}C$ showed good apparent density $4.90g/cm^3,$ and magnetic properties of initial permeability 164 and quality factor 72. As the calcination temperature increase, the grain size of NiCuZn-ferrite increased with irregular grain distribution and its magnetic properties were deteriorated.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.164-164
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• 2003

UV 발광소자 재료로서 유망한 ZnO film을 ALE법으로 증착하고 photoluminescence특성을 조사하였다. Zn소스로서 DEZn(Diethylzinc)를, 산소 소스로서 DI water를 사용하였고 $N_2$ gas로서 챔버내에 주입된 소스물질을 purge하였다. ALE 공정온도 범위인 17$0^{\circ}C$와 CVD 반응온도 범위인 40$0^{\circ}C$로 ZnO 박막을 증착하고 이 시편을 산소 분위기에서 600-100$0^{\circ}C$의 온도로 1시간 동안 열처리하였다. 그리고 He-Cd laser를 사용하여 photoluminescence를 측정하였다. 17$0^{\circ}C$와 40$0^{\circ}C$ 에서 증착된 시편 모두 as-grown 상태에서는 거의 발광특성을 나타내지 못하였으나 후열처리를 거치면서 발광특성을 나타내었고 열처리 온도가 높을수록 발광강도가 증가하였다. 40$0^{\circ}C$에서의 증착된 시편의 경우는CVD반응이 발생하여 Zn-Zn결합이 많이 생성되어 열처리 온도가 증가하여도 발광강도가 약하였고 가시광 영역의 발광 또한 크게 증가하였으며 17$0^{\circ}C$에서 증착된 시편의 경우는 열처리 온도가 증가할수록 UV영역의 발광강도만이 크게 증가하였으며 가시광 영역의 발광은 거의 증가하지 않았다.