Papers by Keyword: Cu

Abstract: The experiment was conducted to select Pteris cretica ecergemiensis with fast growing and high enrichment of heavy metals among twenty plants and to evaluate its rule in accumulating Cu and Ni and the biological and biochemical functions using the solution culture method. The results showed that: (1) The Pteris cretica ecergemiensis had a good growth, and a high ability to accumulate the Cu and Ni with the interction effects of Cu and Ni. (2) With the increase of Cu and Ni concentration, the activities of SOD and CAT increased at first and then reduced, and the proline content increased. In conclusion, the Pteris cretica ecergemiensis is one of potential species for the great remediation of heavy metal pollution.

Abstract: This paper focused on the Cu alloy elements macro segregation of large squeeze casting wheel hub, analysed element segregation on the wheel axle, wheel arm and wheel rim. Three positions on the hardness and mechanical properties were tested, researched the influence of element segregation on the hardness and mechanical properties.

Abstract: The writer successfully obtained brazed Cu-Al joint by using vacuum brazing method, and also conducted an analysis for the microstructure morphology of the joint. The result shows that: The interface of the brazed Cu-Al joint includes three parts---the transition area on the Cu side, the central brazing seam area and the transition area on the Al side. Formed between the brazing seam area and the Cu substrate are the Cu₃Al₂ and CuAl₂ layers, and the average width of the transition area of Cu₃Al₂ is 12 μm while that of CuAl₂ 8 μm. The brazing seam area is mainly composed of α-Al solid solution, Cu₃Al₂ and CuAl₂ metal compounds, in addition, the ε-Cu₁₅Si₄ phase, the Al-Si phase and CuZn₂ phase are also formed. These phases present themselves in the state of acicular compounds, which are dispersed in the brazing seam area.

Abstract: Heavy metal was the biggest obstacles of sludge harmless and resources utilization. Studies have been conducted to investigate the effect of salinity on heavy metal from excess sludge. The static experiments were carried out to observe the release of Cu and Pb at four levels of salinity (20‰, 25‰, 30‰, 35‰). The results showed that Cu and Pb presented a similar trend over time: The concentration gradually increased over time in the early period, when reaching the highest value it begun to decrease, until relatively stabilized. Cu and Pb were more favorable to release in higher salinity levels, especially 35‰. The maximum concentration of Cu and Pb was 0.121ug.L-1 and 1.056 ug.L-1, respectively. And Pb was easier to release than Cu.

Abstract: NTC thermistor paste for printing thermal sensors on alumina was formed of very fine Ni_0.5Cu_0.2Zn_1.0Mn_1.3O₄ thermistor powder obtained by a combined mechanical activation/thermal treatment process, organic vehicle and glass frit. Sheet resistivity was measured using an R-test matrix and it was much lower than the value determined for pure nickel manganite thermistors. The thermistor exponential coefficient was calculated from the R[ diagram measured in the temperature range-30 to +120°C in a climatic chamber. Thick film segmented thermistors with reduced dimensions (optimized construction) were printed sequentially layer by layer, dried and fired at 850°C/10 min in air. Electrodes were printed of PdAg conductive and solderable paste. The samples obtained were characterized by electrical and thermal measurements. The obtained NTC segmented thermistors with reduced dimensions were applied in a thermal sensor for water flow in the water mains. It contained a cold thermistor for measuring input water temperature and a self-heating thermistor for measuring the dependence of water current on water flow rate at a set input voltage power. Initial measurements show that the thermal sensor system requires a low input voltage power making it much easier and safer for operation.

Abstract: A copper rod/FeSiB amorphous ribbon/copper rod sandwich laminated composite material has been successfully fabricated by co-pressing at temperatures within supercooled liquid region. The bonding interface has been characterized by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Results showed that a good bonding interface could be obtained only when the initial surface were carefully polished. The diffusion zone confirmed by EDS is about 60nm, indicating the bonding is in atomic metallurgical level via limited diffusion. The present results show that even the diffusion length is very small, diffusion bonding in the supercooled liquid region could be an effective way for fabricating Fe-based metallic glass/Cu laminated composites

Abstract: Room temperature rolling tests were performed on a bulk nanostructured Cu with an average grain size of 90 nm. The results indicated a high thickness reduction ( ) of 92% without crack and an increased {220} texture as the rolling processes continued. Microstructure evolution of the deformed nanostructured Cu could be characterized by several deformation stages. Grain growth and coalescence was prevalent in the early deformation stage, while grain boundaries were impaired and replaced by dislocation interactions when 24%. Microhardness of the deformed nanostructured Cu increased sharply to a maximum value of 1.61 GPa at 8% and then slightly decreased to 1.58 GPa at 92%.

Abstract: Humic acid (HA) and 3-Mercaptopropyltriethoxysilane (MPTES) were successfully coated onto the surface of Fe₂O₃ (α and γ) nano-particles as characterized using IR and BET-N2 analysis, the potential use of the naked and functionalized nano-Fe₂O₃ particles as novel nano-sorbents for removal of Cd, Pb and Cu ions in solution was investigated in this study. The result indicated that the sorption of Cd, Pb and Cu ions by the nano-particles can be fitted well using langmuir isotherm; all the adsorbents exhibited definitely adsorption ability to Cd, Pb and Cu ions in solution. The sorption maximum and sorption affinity on the nano-particles for Pb (aq) were always higher than Cu (aq) and Cd (aq), the sorption maxima for the Pb, Cd and Cu followed the order Pb>Cu>Cd. Among the nano-sorbents, the Fe₂O₃ (α and γ) nano-particles coated with HA exhibited higher sorption ability to metal ions than the naked and thiolated Fe₂O₃ nano-particles, the sorption maxima of α-Fe₂O₃/HA for Pb(aq) reached 151.5 mg/g, which was significantly higher than the values of 116.3 and 84.0 mg/g observed for the α-Fe₂O₃ and α- Fe₂O₃/MPTES particles. However, no increased sorption maxima was observed for the thiolated Fe2O3 nano-particles (Fe2O3/MPTES) for the metal ions compared with the naked Fe₂O₃ nano-particles in this study. The greater capability of Fe₂O₃/HA to adsorb Cd(aq), Pb(aq), Cu(aq) indicates its potential use as another promising way to remediate metals-contaminated water.

Abstract: Cu supported on acid-treated sepiolite catalysts (xCu/H-Sep, x = 0  20.0 wt%) or Cu-Fe mixed supported on acid-treated sepiolite catalysts (yFe-10Cu/H-Sep, y = 0  20.0 wt%) were prepared by the incipient wetness impregnation method. The xCu/H-Sep and yFe-10Cu/H-Sep catalysts were characterized by means of XRD, BET, XRF, XPS, and H2-TPR techniques, and their catalytic activities were evaluated for the SCR of NO with propylene. XPS and XRD results indicate that there was the co-presence of Cu+-Cu2+ and Fe2+-Fe3+ over the surfaces of yFe-10Cu/H-Sep catalysts, and there was a strong interaction between Cu, Fe and sepiolite. High promotional effect of iron additive on the catalytic performance of Cu/H-Sep catalyst were found in C3H6-SCR of NO reaction. The highest activity of 65% NO conversion was obtained over 15Fe-10Cu/H-Sep catalyst at 280 oC under the condition of 1000 ppm NO, 1000 ppm C3H6, and 5% O2. The high catalytic activity of 15Fe-10Cu/H-Sep catalyst for NO reduction was due to its high reducibility to activate C3H6 to selectively reduce NO in the presence of excess O2. The high dispersion of copper oxides and strong metal-support interaction over 15Fe-10Cu/H-Sep catalyst also improve its catalytic performance.

Abstract: Cermets Ti(C，N)_80%Co_(10-x)% TiC_10% Cu_x%(wt%，x=0，1，2，3， 4， 5) were prepared by powder metallurgy method under vacuum condition at 1500°C and the effects of Cu element to the electrical resistivity and flexural strength were studied in this paper. It turns out the electrical resistivity of the samples obviously decreases with the introduction of Cu element, but the electrical resistivity of the samples increases when the amount of Cu element in the samples becomes more. The flexural strengths of the samples decrease with the amount of Cu element increasing. Ti（C，N）_80% Co_9%TiC_10% Cu_1% shows the lowest electrical resistivity and the biggest flexural strength, 7.35*10-7Ω•m and 50.6Mpa. This may be due to the big wetting angle between Cu and the powders of the based body. With the amount of Cu element increasing, the obvious interfaces are made thus the electrical resistivity becomes bigger.