A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiti...A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.展开更多
Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intak...Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intake fails to compensate. The aim of this research is to determine the status of trace elements (calcium, copper, magnesium, selenium and zinc) in pregnant women in the city of Kisangani. Methods: We carried out an analytical cross-sectional study of non-pregnant and pregnant women living in Kisangani, from 05 October 2023 to 05 January 2024. Concentrations of trace elements in sera were analysed using an inductively coupled plasma mass spectrophotometer (ICP-MS Agilent 7700X). Statistical analysis of the data was performed using R software version 4.3.0. Results: The mean age was 26.3 ± 6.7 years;the mean copper and magnesium levels in the serum of pregnant women were 12.58 ± 1.13 micromol/l and 1.03 ± 1.03 mmol/l respectively. The medians for calcium and zinc were 1.49 mmol/l and 8.42 micromol/l. The selenium mode was 0.41 micromol/l. Variations in trace element levels in sera of pregnant women were 0.94 - 2.22 mmol/l for calcium;0.31 - 0.78 micromol/l for selenium;and 7.29 - 12.72 micromol/l for zinc;11.04 - 14.99 micromol/l for copper, and 0.082 - 1.05 mmol/l for magnesium. Conclusion: Serum trace element concentrations in pregnant women were lower than those observed in non-pregnant women. Trace element reserves in pregnant women depended on their nutrient status prior to pregnancy, hence, there was an urgent need for trace element balance prior to pregnancy.展开更多
The phenomena of tuyere upward-warp have been found at No.6 blast furnace in Kunming Steel Company China after its blow-in, which has made a great impact on the practical production of the furnace. Thus, a number of e...The phenomena of tuyere upward-warp have been found at No.6 blast furnace in Kunming Steel Company China after its blow-in, which has made a great impact on the practical production of the furnace. Thus, a number of efforts have been made to elucidate the mechanism of this phenomenon. The results of investigation and tests revealed that the enrichment and expansion of zinc in the tuyere bricks is the main factor leading to the tuyere upward-warp. The eroding behavior of zinc is that the inner structure of the tuyere bricks turns from dense to loose with entering, enriching and expanding of zinc, which forms spot-like→stripe-like→ditch-like→vein-like→tumorlike eroding passage. Additionally, it is found that the sequence of deleterious ele- ments entering the tuyere refractory is K, Na, Zn and Pb, respectively. Finally, the phenomena and process of zinc crystallization and growth in the refractory have been clearly observed and recorded during this investigation.展开更多
Zinc supplementation can help maintain learning and memory function in rodents. In this study, we hypothesized that zinc supplementation could antagonize the neurotoxicity induced by aluminum in rats. Animals were fed...Zinc supplementation can help maintain learning and memory function in rodents. In this study, we hypothesized that zinc supplementation could antagonize the neurotoxicity induced by aluminum in rats. Animals were fed a diet containing different doses of zinc （50, 100, 200 mg/kg） for 9 weeks, and orally administered aluminum chloride （300 mg/kg daily） from the third week for 7 consecutive weeks. Open-field behavioral test results showed that the number of rearings in the group given the 100 mg/kg zinc supplement was significantly increased compared with the group given the 50 mg/kg zinc supplement. Malondialdehyde content in the cerebrum was significantly decreased, while dopamine and 5-hydroxytryptamine levels were increased in the groups given the diet sup- plemented with 100 and 200 mg/kg zinc, compared with the group given the diet supplemented with 50 mg/kg zinc. The acetylcholinesterase activity in the cerebrum was significantly decreased in the group given the 100 mg/kg zinc supplement. Hematoxylin-eosin staining revealed evident patho- logical damage in the hippocampus of rats in the group given the diet supplemented with 50 mg/kg zinc, but the damage was attenuated in the groups given the diet supplemented with 100 and 200 mg/kg zinc. Our findings suggest that zinc is a potential neuroprotective agent against alumi-num-induced neurotoxicity in rats, and the optimal dosages are 100 and 200 mg/kg.展开更多
This paper is aimed to propose a three-dimensional model which would be used for investigation on the mechanical behavior of single-layered zinc oxide nanosheets. To develop this model, molecular mechanics is coupled ...This paper is aimed to propose a three-dimensional model which would be used for investigation on the mechanical behavior of single-layered zinc oxide nanosheets. To develop this model, molecular mechanics is coupled with the density functional theory. Simulating the hexagonal lattices of nanosheets as a hexagonal mechanical structure composed of structural beam elements, the buckling behavior of zinc oxide nanosheets is studied. Effects of different parameters on the stability of armchair and zigzag nanosheets are examined. It is shown that the buckling forces of zigzag nanosheets are slightly greater than those of armchair ones. However, with increasing size of nanosheets the effect of atomic structure on the stability of nanosheets diminishes.By studying the effect of end conditions on the buckling behavior of nanosheets, it is shown the stability of nanosheets is affected significantly by boundary conditions.展开更多
基金Key Technologies R&D Program of Tianjin (06YFGZGX02400)
文摘A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.
文摘Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intake fails to compensate. The aim of this research is to determine the status of trace elements (calcium, copper, magnesium, selenium and zinc) in pregnant women in the city of Kisangani. Methods: We carried out an analytical cross-sectional study of non-pregnant and pregnant women living in Kisangani, from 05 October 2023 to 05 January 2024. Concentrations of trace elements in sera were analysed using an inductively coupled plasma mass spectrophotometer (ICP-MS Agilent 7700X). Statistical analysis of the data was performed using R software version 4.3.0. Results: The mean age was 26.3 ± 6.7 years;the mean copper and magnesium levels in the serum of pregnant women were 12.58 ± 1.13 micromol/l and 1.03 ± 1.03 mmol/l respectively. The medians for calcium and zinc were 1.49 mmol/l and 8.42 micromol/l. The selenium mode was 0.41 micromol/l. Variations in trace element levels in sera of pregnant women were 0.94 - 2.22 mmol/l for calcium;0.31 - 0.78 micromol/l for selenium;and 7.29 - 12.72 micromol/l for zinc;11.04 - 14.99 micromol/l for copper, and 0.082 - 1.05 mmol/l for magnesium. Conclusion: Serum trace element concentrations in pregnant women were lower than those observed in non-pregnant women. Trace element reserves in pregnant women depended on their nutrient status prior to pregnancy, hence, there was an urgent need for trace element balance prior to pregnancy.
基金supported by Program for New Century Excellent Talents in University(NCET-2008-0099)
文摘The phenomena of tuyere upward-warp have been found at No.6 blast furnace in Kunming Steel Company China after its blow-in, which has made a great impact on the practical production of the furnace. Thus, a number of efforts have been made to elucidate the mechanism of this phenomenon. The results of investigation and tests revealed that the enrichment and expansion of zinc in the tuyere bricks is the main factor leading to the tuyere upward-warp. The eroding behavior of zinc is that the inner structure of the tuyere bricks turns from dense to loose with entering, enriching and expanding of zinc, which forms spot-like→stripe-like→ditch-like→vein-like→tumorlike eroding passage. Additionally, it is found that the sequence of deleterious ele- ments entering the tuyere refractory is K, Na, Zn and Pb, respectively. Finally, the phenomena and process of zinc crystallization and growth in the refractory have been clearly observed and recorded during this investigation.
基金was funded by the National Nature Science Foundation of China,No.30872098,30901185the National Nature Science Foundation of Tianjin,No.05YFJMJC 05500the Medical Science and Technology Project of Chinese PLA,No.13QNP069.
文摘Zinc supplementation can help maintain learning and memory function in rodents. In this study, we hypothesized that zinc supplementation could antagonize the neurotoxicity induced by aluminum in rats. Animals were fed a diet containing different doses of zinc （50, 100, 200 mg/kg） for 9 weeks, and orally administered aluminum chloride （300 mg/kg daily） from the third week for 7 consecutive weeks. Open-field behavioral test results showed that the number of rearings in the group given the 100 mg/kg zinc supplement was significantly increased compared with the group given the 50 mg/kg zinc supplement. Malondialdehyde content in the cerebrum was significantly decreased, while dopamine and 5-hydroxytryptamine levels were increased in the groups given the diet sup- plemented with 100 and 200 mg/kg zinc, compared with the group given the diet supplemented with 50 mg/kg zinc. The acetylcholinesterase activity in the cerebrum was significantly decreased in the group given the 100 mg/kg zinc supplement. Hematoxylin-eosin staining revealed evident patho- logical damage in the hippocampus of rats in the group given the diet supplemented with 50 mg/kg zinc, but the damage was attenuated in the groups given the diet supplemented with 100 and 200 mg/kg zinc. Our findings suggest that zinc is a potential neuroprotective agent against alumi-num-induced neurotoxicity in rats, and the optimal dosages are 100 and 200 mg/kg.
文摘This paper is aimed to propose a three-dimensional model which would be used for investigation on the mechanical behavior of single-layered zinc oxide nanosheets. To develop this model, molecular mechanics is coupled with the density functional theory. Simulating the hexagonal lattices of nanosheets as a hexagonal mechanical structure composed of structural beam elements, the buckling behavior of zinc oxide nanosheets is studied. Effects of different parameters on the stability of armchair and zigzag nanosheets are examined. It is shown that the buckling forces of zigzag nanosheets are slightly greater than those of armchair ones. However, with increasing size of nanosheets the effect of atomic structure on the stability of nanosheets diminishes.By studying the effect of end conditions on the buckling behavior of nanosheets, it is shown the stability of nanosheets is affected significantly by boundary conditions.
