Applied Mechanics and Materials Vols. 543-547

Abstract: The effects of different parameters on adsorption of Zn²⁺with coconut activated carbon were studied. The adsorption characteristics on Zn²⁺ by coconut activated carbon were explored in this study. The contact time to reach adsorption equilibrium was 80 min. The suitable conditions for adsorption of Zn²⁺ by coconut activated carbon were exhibited as follows: the dosing ratio was 0.5 g/10 mg·L^-1, the contact time was 80 min, the temperature was 37°C and the pH was 7.

Abstract: For lack of existing low temperature solder paste , developed a low-temperature Sn-Bi solder paste, focused on finding the optimal formula , at the same time on the flux of the solder paste, is printing performance and wettability can be tested through performance test to find the optimal flux formula.

Abstract: The graphene oxide (GO) was prepared by oxidizing flake graphite via the modified Hummers method, and it was halogenated by thionyl chloride after clearing. Then it became amino-graphene (AG) by the action of ethanediamine in methylbenzene. The as-prepared AG was dried and pulverized, then was crushed into slice-like electrode at high pressure using machine made-oneself. The GO and AG in this experiment was analyzed and characterized by SEM, TEM, XRD AND FT-IR. The cyclic voltammetry (CV) was used to illustrate the electrochemical performance of AG electrode. The results revealed that groups containing oxygen of the GO were obviously reduced and the COOH was replaced by-NH₂, and the prepared electrode could be applied to the electrochemical catalysis.

Abstract: The thermal tunable behavior of polyethylene inverse opal photonic crystals was investigated and the mechanism of this behavior was illustrated. Based on these researches, a method of determination of melting point was established. This principle of such method is that at the temperature of above the melting point, the molecular chain of the materials started to move and caused the destruction of the ordered nanostructure of the inverse opal. This destruction could be real-time monitored by the reflectance spectra. In addition, this process could also be observed by naked eyes because the structure color of the materials was also changed. Thus, the melting point of the materials could be detected by our method without using complex and expensive analyzer.

Abstract: Mineral polymer is a new category of inorganic non-mental materials, which was manufactured from metakaolin in this paper. Changes of metakaolin in the polymerization could be described as: (1) the glassy parts of the metakaolin were dissolved in the high molar alkaline solution and some SiO, AlO bonds of them broke; (2) at the presence of OH-and Na+, these broken bonds formed aluminosilicate gel and then transformed into zeolitic precursors with changing compositions and concentrations of the solution; (3) by dehydration, these zeolitic precursors changed into the amorphous phase materials. NMR analysis indicated that in the geopolymeric products cured for 28 days, Q⁴(2Al) was the principal form of Si element and the content of four coordinate Al was increasing with the reaction. The experimental results provided a good basis for understanding the reactive mechanism of polymerization during processing of geopolymer products.

Abstract: Based on the properties of gold ore, several effects, such as grinding fineness, system of flotation pharmaceutical, were researched in the flotation experiment. The results showed that with the grinding fineness-0.074mm 65%, pH=8.5, 2# oil 60 g/t, butylxanthate 140 g/t and Butylamine black medicine 50 g/t, good indexes were obtained as the following: grade of Au rough concentrate is3.24g/t, recovery of Au is 36.90%.

Abstract: The properties of the flue dust of an iron-making plant and the results of separation experiment were given. The test results show that the flue dust could be enriched by flotation-gravity-magnetic separation technology to produce carbon concentrate and iron concentration. The results showed that 56.67% iron concentrate and 65.29% carbon concentrate could be got.

Abstract: Hercynite (FeAl₂O₄) with octahedral structure rarely exists in nature and can only be synthesized artificially. However, it is hard to synthesize high purity hercynite. To date, it is known that two main synthetic methods, sintering and electro-fusion processes, are available to synthesize hercynite. Specimens synthesized by the two processes are different in Microstructure and phase compositions. The variations are researched by SEM, XRD and EDS.

Abstract: In this paper, we added silicon nitride in the samples of common bauxite and the bauxite with high potassium and sodium oxide content, treated them at the high temperature of 1,400°Cand 1,500°C, and then conducted analysis with XRD, SEM and EDS. The results are as follows: After adding β-Si3N4 in sintered bauxite, the partial pressure of oxygen in the composite materials will be reduced, the decomposition and volatilization of compounds with high partial pressure of oxygen (such as potassium oxide and sodium oxide) will be promoted, the content of these compounds in the bauxite will be lowered, and the hazards of the compounds with low melting point will be weakened; meanwhile, with the reduction of potassium, sodium and iron oxide, the lattice of alumina will be activated, the β-Sialon phase will be easily formed and the high temperature properties of sintered bauxite materials will be strengthened.

Abstract: Due to the electrical and physical analyses, the robust negative voltage unipolar resistive switching behaviors in Ti/ZrO₂/Ti/ZrO₂/Pt device have been investigated. The Ti diffusion in ZrO₂ film can generate more amounts of oxygen vacancies in it, which leads the lower value and narrower variation in forming voltage. Moreover, the good performances with more than 1000 switching cycles and long retention test can be achieved in the present device.