• 한국표면공학회지
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• 제36권3호
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• pp.256-262
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• 2003

The current efficiency and the composition of Zn-Cr and Zn-Cr-X (X : Co, Mn) alloy electrodeposits were investigated by using chloride bath with EDTA auditive and flow cell plating system. The current efficiency of Zn-Cr alloy decreased with increasing current density, while it increased with the content of Co and Mn of the Zn-Cr-X alloy bath in high current density region. The Cr content in Zn-Cr alloy increased from 1.4-2.7 to $28wt\%$ with increasing current density and the phase structure of the alloys changed from $\eta-Zn$ through $\eta-Zn+\gamma'-ZnCr\;to\;\gamma'-ZnCr$ with Increasing Cr content of the alloys. The Co content in Zn-Cr-Co alloys increased with Co content of the bath, while Cr content of the alloy increased or decreased in low current density region $(10-75A/dm^2)$ or high current density region $(75-100A/dm^2)$, respectively. $\gamma-ZnCo$ phase was formed in the Zn-Cr-Co alloy with above $9.0wt\%$ Co. The content of Mn and Cr in Zn-Cr-Mn alloys increased or decreased with the increase of current density in high current density region, respectively while Cr content of the alloy decreased noticeably with the increase of Mn content in the bath. Two phases of $\delta_1-ZnMn$ and $\gamma'-ZnCr$ were formed in the Zn-Cr-Mn alloy with above $8.6wt\%$ Mn.

• 한국식품영양과학회지
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• 제23권5호
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• pp.718-724
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• 1994

The study was conducted to investigated the effect of dietary levels of zinc (Zn) on lipid metabolism in cadmium (Cd) treated rats. Sixty male Sprague-Dawley rats weighing about 110$\pm$10g were divided into 6 groups. The Zn levels were low (0ppm), control (30 ppm) and Cd-treated groups were administrated with Cd chloride (5.0mg/kg of body weight) by oral intubation at the same time once a week. Serum total lipid, triglyceride , total cholesterol and DHL-cholesterol contents decreased significantly in low Zn group. In serum dietary high Zn group, it decreased significantly in the content of triglyceride but total cholesterol and HDL- cholesterol revealed increase slightly . Total lipid and triglyceride contents increased by Cd oral intubation, but triblyceride content of control group decreased significantly in Cd-treated groups. HDL-cholesterol content also decreased by Cd oral intubationl. Cd-treatment increased total cholesterol content in low Zn group. Liver triglyceride content increased as dietary Zn level became more increasing and total lipid was not influenced by dietary Zn levels. Liver cholesterol content was higher in low and high Zn groups than that of control group. Liver phospholipid content decreased in low Zn group . Oral intubation of Cd increased in the contents of triglyceride and total lipid. The content of liver Zn was not influenced by the dietary low Zn but that of serum showed a remarkable increased . Oral Cd intubation increased the Cd contents of liver and serum.

• 한국세라믹학회지
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• 제31권11호
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• pp.1396-1400
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• 1994

Electrical properties in the ZnO-Bi2O3-CoO-Zn7Sb2O12 system were investigated with Zn7Sb2O12 content (0.1~2 mol%). The increase of the Zn7Sb2O12 content inhibited the grain growth of ZnO, which showed a narrow grain size distribution of ZnO. The breakdown voltage (Vb) increased markedly with 1 mol% Zn7Sb2O12 addition due to the grain growth control behaviour of the Zn7Sb2O12 . The nonlinear I-V characteristic was significantly influenced by the Zn7Sb2O12 content (or Bi2O3/Zn7Sb2O12 ratio). Addition of 0.5 mol% Zn7Sb2O12 showed the highest nonlinear coefficient ($\alpha$) of 43. The leakage current in prebreakdown region was decreased with increasing Zn7Sb2O12 content.

• 한국전기전자재료학회논문지
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• 제27권7호
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• pp.443-447
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• 2014

ZnO crystals with different morphologies were synthesized through a thermal evaporation of Zn-Mn mixtures in air. The morphology was dependant on the Mn content in Zn-Mn mixture. The morphology was changed from rod to tetrapod shape with decreasing Mn content in Zn-Mn mixture. The result indicates that the concentration of Mn might be responsible for the different morphologies of ZnO crystals. XRD spectra showed that the ZnO crystals had a hexagonal wurtzite crystal strutures. For all the samples, room temperature cathodoluminescence spectra showed a ultra-violet emission at 380 nm and a green emission at around 500 nm. However, the intensity ratio of ultra-violet emission to green emission was significantly different with the Mn content in the source material.

• 한국주조공학회지
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• 제36권4호
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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.

• 한국환경농학회지
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• 제4권1호
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• pp.11-17
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• 1985

Zn와 Cd을 무저(無底)폿트(${\phi}30cm{\times}70cm$)에 Cd는 5, 10, 30ppm, Zn은 150, 300, 600ppm으로 처리(處理)하고 옥수수(수원(水原) 19호(號))를 파종(播種)하여 발아후(發芽後) 15일(日), 30일(日), 45일(日)의 식물체(植物體) 생육(生育), 엽중(葉中) peroxidase활성(活性), 엽녹소(葉綠素) 합량(合量), 무기성분(無機成分) 함량(含量) 및 중김속(重金屬) 함량(含量)을 조사(調査)한 결과(結果)는 다음과 같다. 1) 토양중(土壤中) Cd, Zn의 첨가농도(添加濃度)가 높아질수록 간장(稈長) 및 건물중(乾物重)이 유의성(有意性)있게 감소하였다. 2) 식물체중(植物體中) Cd함량(含量)이 높아질수록 엽중(葉中) peroxidase 활성(活性)은 증가(增加)하나, Zn은 함량(含量)이 높아질수록 감소(減少)하는 경향(減少)이었다. 3) 식물체중(植物體中) Cd, Zn 농도(濃度)가 증가(增加)할수록 chlorophyll함량(含量)은 감소(減少)되었다. 4) 토양중 Cd 첨가농도(添加濃度)가 높아질수록 식물체중(植物體中) N함량(含量)은 증가(增加)되나 P, K, Ca, Mg, $SiO_2$함량(含量)은 감소(減少)되었다. 반면(反面) 토양중(土壤中) Zn첨가농도(添加濃度)가 높아질수록 P 및 SiO함양(含量)은 증가(增加)되나 N, Ca, Mg함양(含量)은 감소(減少)되는 경향(傾向)이었다. 5) 식물체중(植物體中) Cd, Zn흡수량(吸收量)은 시기(時期)가 경과할수록 증가(增加)하나 이들 함양(含量)은 일정(一定)한 경향(傾向)이 없었다. 6) 시일(時日)이 경과함에 따라 식물체중(植物體中) Cd흡수(吸收)는 Zn의 첨가농도(添加濃度)가 높아질수록 감소(減少)된 반면(反面) 식물체중(植物體中) Zn흡수(吸收) Cd의 낮은 첨가농도(添加濃度)에서 감소(減少)되었다.

• 한국세라믹학회지
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• 제37권4호
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• pp.314-319
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• 2000

Microstructueral development and electrical properties in ZnO-Bi2O3-ZnAl2O4 system were investigated with ZnAl2O4 content(0.1~1.0 mol%). The shrinakge of specimens started around $700^{\circ}C$ and finished at 110$0^{\circ}C$, reaching a maximum shrinkage rate at 80$0^{\circ}C$. The shrinkage rate is strongly related to the fromation of a Bi-rich liquid. The increase of the ZnAl2O4 content inhibited the grain growth of ZnO. Most of ZnAl2O4 particles located at the grain boundaries were about 2~3${\mu}{\textrm}{m}$. ZnO grain size changed little up to 110$0^{\circ}C$, but increased markedly above 115$0^{\circ}C$, especially at lower ZnAl2O4 content. Drastic decreasing in breakdown voltage(Vb) with increasing temperature is expected to be dependent on the ZnO grain size and the distribution of the largest grains between the electrode. The nonlinear I-V characteristic was significantly influenced by the ZnAl2O4 content, which exhibited a maximum value at about 15${\mu}{\textrm}{m}$ of ZnO grain size.

• 열처리공학회지
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• 제36권4호
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• pp.223-229
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• 2023

This work was intended to investigate the effects of Zn content on microstructure and hardness of discontinuous precipitates (DPs) produced by continuous cooling (CC) in Mg-8%Al-X%Zn alloys with 0%, 0.5% and 1% of Zn contents (wt%). The DPs in the alloys possessed a wide range of (α+β) interlamellar spacings, which is attributed to the different transformation temperatures during CC. The higher Zn content resulted in the lower level of interlamellar spacings of the DPs, along with thinner and larger volume fraction of β phase layer in the DPs. It is noted that the DPs in the alloy with higher Zn content exhibited higher hardness, and that the ratio of increase in hardness of the DPs to that of the as-cast state was also increased with increasing Zn content. The reason was discussed on the basis of microstructural differences of the DPs in the Mg-8%Al-X%Zn alloys.

• 한국표면공학회지
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• 제28권1호
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• pp.14-22
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• 1995

The effects of iron content in coated layer, surface roughness and lubricants on the formability of commercial Zn-Fe alloy electroplated steel sheets used for automotive bodies were investigated. The higher the iron content in deposit, the lower the friction coefficient of Zn-Fe alloy electroplated steel sheets. The surface roughness of coated layer hardly influenced the frictional characteristics. The formability of Zn-Fe alloy electroplated steel sheets was found to be more affected by the lubricant than by iron content in Zn-Fe alloy electrodeposit.

• 한국표면공학회지
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• 제36권6호
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• pp.423-429
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• 2003

It has been investigated corrosion resistance and crystal structure of Zn-Cr coatings fabricated by electroplating method and electron-beam physical vapor deposition method(EB-P VD). The electroplated Zn-Cr alloy consists mainly of η'-Zn phase for the lower Cr content than 7.9 wt% Cr and ${\gamma}$'-ZnCr phase for the higher Cr content. In the Zn-Cr alloy fabricated by EB-PVD the ${\gamma}$'-ZnCr phase appeared clearly at 3 wt% Cr and it became the sole phase at 50 wt%Cr. The amount of η'-Zn phase decreased obviously with increasing Cr content when it exceeded 15 wt% Cr. The electrochemical measurement of the electroplated Zn-Cr film has shown corrosion potential of about -1000 mV. The current density of active region and the amount of dissolved Zn and Cr decreased significantly with increasing Cr content. The electrochemical characteristics of Zn-Cr alloy fabricated by EB-PVD have shown that the alloy of 50 wt% Cr had the highest corrosion potential(-500 mV) and the lowest critical passive current density than that of the electroplated.