• Asian-Australasian Journal of Animal Sciences
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• 제21권7호
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• pp.1048-1052
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• 2008

The objective of this study was to determine the effect of sodium selenite and zinc-L-selenomethionine on performance and egg Se concentration in laying hens. Two hundred and twenty-four CP Browns aged 71 weeks were divided according to a $2{\times}3$ factorial in a completely randomized design. One more group without additional Se supplementation was used as a negative control. Each treatment consisted of four replicates and each replicate contained eight laying hens. The dietary treatments were T1: basal diet; T2, T3 and T4: basal diets plus 0.3, 1.0 and 3.0 mg Se from sodium selenite/kg, respectively; T5, T6 and T7: basal diets plus 0.3, 1.0 and 3.0 mg Se from zinc-L-selenomethionine/kg, respectively. The findings revealed that feed conversion rate/kg eggs, egg production, egg weight, Haugh units and eggshell thickness were not affected by source and level of Se (p>0.05). Increasing level of dietary Se significantly increased (p<0.05 the Se content of eggs. Zinc-L-selenomethionine markedly increased p<0.05 egg Se concentration as compared with sodium selenite. The results indicated that Se source did not influence performance of laying hens. However, zinc-L-selenomethionine increased p<0.05 egg Se concentration more than sodium selenite.

• 멤브레인
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• 제4권2호
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• pp.106-112
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• 1994

$ZnSo_4{\cdot}7H_2O$에 의한 모델폐수에서 Zn 농도 및 pH를 변화하여 역삼투 실험하였고, Zn용액의 pH에 따라 아연의 제거율은 상당히 변화하였고, pH 3.0~11.5 범위에서 실험한 바 pH 8.3일 때가 아연제거율은 99.9% 이상, 투과 속도는 $1.49 {\times} 10^{-3}cm/sec$로 가장 큰 값을 보였다. 아연모델폐수에 Cyanide를 아연농도와 동량으로 첨가하였을 때, 아연은 99%, Cyanide는 93% 정도 제거가 가능하였다. 또한 첨가제로 음이온계면활성제 등을 첨가하여 실험한 결과, Membrane에서의 투과속도가 $0.76 {\times} 10^{-3}cm/sec$로 현저히 감소하였다.

• 자원환경지질
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• 제10권3호
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• pp.99-105
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• 1977

Mineralogical study of original and crushed zinc ores as well as mill products was made in order to find out the cause of low-grade concentrate and the scheme of raising its grade. Low-grade concentrate is due to 1) the abundance of other independent sulfides (arsenopyrite, pyrrhotite, chalcopyrite, stannite) and silicate (quartz) in the zinc concentrate, 2) the presence of composite grains of sphalerite and other sulfides or silicate, 3) the presence of a lot of very fine-grained particle of stannite and chalcopyrite within the sphalerite grains, and 4) the high content of iron in sphalerite. It is proposed that further crushing and other appropriate processing should be made in order to increase the grade of zinc concentrate.

• 한국조리학회지
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• 제3권
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• pp.291-313
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• 1997

This experiment was conducted to study the effects of dietary zinc and ethanol on the mineral contents of serum and changes of the liver tissue. Eighty male rats of Sprague-Dawley strain with average weight of 80$\pm$5g were divided into five groups according to zinc levels(5ppm and 100ppm), ethanol and isocaloric sucrose feedings. The rats were sacrificed after 4 and 7 weeks of feeding periods. The results are summarized as follows. 1. There was a decrease of weight gain in the ZD group compared with the C group and also decreased in the CE and ZDE groups fed the ethanol solution. The feed intake was decreased in the ZD and ZDE groups, and the feed efficiency was also greatly reduced in the ZDE group. 2. The liver weight of the ZD and ZDE groups was increased, however, the weight of testis was decreased in the same groups. And the weight of spleen was decreased in the ZD group. 3. The AST and ALT activities of serum were significantly increased in the ZDE group. 4. The content of serum zinc was influenced by the dietary zinc level, and the amount was significantly decreased in the ZD group. But the content of serum copper was remarkably increased in the ZD grou. The calcium and magnesium contents of serum were decreased in the ZD and ZDE groups. 5. The morphological changes of the liver tissue were not different among the C, CE and PF groups, but the abllooning denaturation of the liver cell together with the infiltration of the local inflammation cell was found in ZD and ZDE groups.

• 한국표면공학회지
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• 제40권1호
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• pp.23-31
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• 2007

The objective of this study is to investigate the effect of Al addition on the reaction behavior of cobalt with molten zinc. Pure cobalt specimen was immersion tested in the three kinds of molten zinc (pure, 0.12%Al added and 0.24%Al added) baths at $460^{\circ}C,\;490^{\circ}C\;and\;520^{\circ}C$. For the understanding of degradation processes, specimens were analyzed with scanning electron microscope (SEM) and energy dispersive spectrum (EDS), and electrochemical stripping method. When 0.12% and 0.24% Al was added in molten zinc baths, three intermetallic compounds layers of ${\gamma},\;{\gamma}_1,\;and\;{\gamma}_2$ were formed on the Co matrix and ${\beta}_1$ layer was not formed between the Co matrix and the ${\gamma}$ layer. Particles of CoAl intermetallic compound were formed at the interface between the ${\gamma}_2$ layer and zinc melt and they did not adhere to the Co-Zn intermetallic layer. Weight loss of the Co specimen increased as Al content in the molten zinc increased and the relationship of weight loss vs. immersion time followed parabolic rate law. Rate controlling process for the reaction rate of Co with Al added molten zinc was analyzed as the diffusion process of Al atom through a boundary layer between the ${\gamma}_2$ layer and the Al added zinc melt.

• 한국식품영양과학회지
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• 제38권9호
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• pp.1174-1178
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• 2009

본 연구는 아연 공급 수준이 비만과 관련된 당대사 이상과 체내 무기질 함량에 미치는 영향을 알아보기 위하여 고지방식이 유도 비만쥐에게 아연을 요구량의 50%, 100%, 200% 수준으로 공급한 후 혈당, 인슐린 및 혈청 아연, 마그네슘, 크롬 함량을 측정하였다. 사료섭취량, 체중증가량, 사료효율 및 각 조직의 무게는 아연 공급 수준에 따른 유의적인 차이를 보이지 않았다. 그러나 혈당과 인슐린 농도는 아연 공급수준에 따라 유의적인 차이를 보여 혈당은 아연 과잉군이 결핍군과 적정군보다 유의적으로 낮게 나타났지만(p<0.05), 인슐린 농도는 아연 과잉군이 결핍군과 적정군보다 유의적으로 높았다(p<0.05). 혈청 아연과 크롬 함량은 아연 공급량에 따른 유의적인 영향을 받지 않았으나, 혈청 마그네슘 함량은 아연 결핍군이 다른 두 군보다 유의적으로 높게 나타났다(p<0.05). 결론적으로 비만군에서 아연 공급 수준에 따라 체내 당대사 및 그와 관련된 무기질 일부가 변화되는 것을 관찰할 수 있었다. 그러므로 비만군에게 아연을 보충 급여하면 인슐린 농도가 증가하며 그 결과 비만으로 발생될 수 있는 고혈당을 낮추는 효과가 있을 것으로 사료된다.

• Preventive Nutrition and Food Science
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• 제15권2호
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• pp.143-146
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• 2010

Organic zinc was included in the diet of broiler chickens to examine its effect on the skin characteristics and the expression level of skin proteins. Broiler chicks (Ross$\times$Ross) were fed a corn-wheat-soybean meal basal diet, either as control or containing an additional 80 ppm of zinc proteinate for 4 weeks, and then five broilers from each treatment were selected randomly, slaughtered, and their skin characteristics were examined. There were significant increases (p<0.05) in thigh skin epidermis and dermis thickness in the chicks fed organic zinc. Collagen content in the skin of broilers was also increased by the addition of organic zinc to the diet. 2D-gel electrophoresis patterns indicated that expression levels of the three proteins, glyoxylase 1, hypothetical protein, and dispersin B were affected by zinc feeding. These results suggest that adding organic zinc to the chicken's feed may contribute to decreased skin tearing.

• 한국세라믹학회지
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• 제55권2호
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• pp.135-139
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• 2018

The glass structure and antibacterial properties of $(65-x)ZnO-xB_2O_3-35P_2O_5$ glasses were investigated. Zinc borophosphate glasses were prepared using a conventional melt-quenching technique at $1000^{\circ}C$. Glass transition temperature and CTE were studied and the structure of zinc borophosphate glasses was evaluated by FTIR. The $Zn^{2+}$ state increase with increasing ZnO content was investigated by XPS and a single sharp Zn $2P_{3/2}$ peak was confirmed, showing that Zn $2P_{3/2}$ exists as $Zn^{2+}$. In order to to evaluate the antimicrobial activity, Escherichia coli (E. coli) was used following the Japanese Industrial Standard JIS Z 2801; the E. coli death rate was found to increase with increasing $Zn^{2+}$ content of glasses.

• 한국표면공학회지
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• 제20권3호
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• pp.118-126
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• 1987

The Zn-Al composite electroplating was studied by using chloride zinc bath containing metal hydroxides $(Zn(OH)_2,\;Al(OH)_3))$ and aluminium powder. The size of Al powder codeposited in the beaker bath with Al powder of-400 mesh was under 10${\mu}m$. The Zn-Al composite was electro-deposited at 40$^{\circ}C$ in the ranges of current density of 5-50 A/$dm^2$ in the flowing electrolyte. The content of aluminium particles codeposited increased slightly with increasing flow rate of electrolyte from 0.5 m/sec to 1.0 m/sec, and decreased with increasing current density from 5 A/$dm^2$ to 50 A/$dm^2$. The content of aluminium particles codeposited by using the electrolyte containing zinc hydroxide(0.1M) was 2~4 wt%. The Al powder was codeposited mainly near the surface layer of the electrodeposits. The dissolution rate of aluminium particles in the electrolyte containing 0.1M $Zn(OH)_2$ and Boric acid was 0.41 g/l. day in comparison with 1.5 g/l. day dissolution rate in pure chloride bath.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.163-172
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• 2022

Zinc-rich epoxy (ZRE) is used to overcome corrosion problems in reinforced concrete (RC) beams and coat steel rebars to protect them from humidity and chlorides. An extra coating layer of Sikadur-31 epoxy (SDE) is utilised to increase bond strength because the use of ZRE reduces the bond strength between concrete and steel rebars. However, the low melting point of SDE indicates that concrete specimens are vulnerable to fire. An experimental investigation on flexural performance of RC beams incorporating ZRE-SDE coating of steel rebars that were destroyed by fire is performed in this study. Twenty beams of five concrete mixes with different cementitious contents were tested to compare fire exposure for coated and uncoated rebars of the same beams at room temperature and determine the optimal cementitious content. Scanning electron microscopy (SEM) was also applied to investigate characteristics of fired mixture samples. Results showed that the use of SDE-ZRE at room temperature improves flexural strengths of the five mixes compared with uncoated rebars with percentages ranging from 8.5% to 12.3%. All beams with SDE-ZRE lost approximately 50% of their flexural strength due to firing. Moreover, the mix incorporating SF (silica fume) of 15% and cement content of 400 kg/m³ introduces optimum behaviour compared with other mixes. All results were supported and verified by the SEM analysis and compressive strength of cubic specimens of the same mixes.