Applied Mechanics and Materials Vols. 543-547

Abstract: In order to investigate the impact of cutting parameters on surface integrity when high-speed turning 58SiMn without cutting fluid, three-factor three-level orthogonal experiments and single factor experiments based on cutting speed and feed rate are employed, and an empirical model is established. The results of analysis of variance (ANOVA) revealed that feed rate is the dominant factor affecting the surface roughness. With the increase of cutting speed and feed rate, residual tensile stress on the surface becomes larger. Along the depth, micro hardness first decreases and then increases.

Abstract: The photonic crystal fiber was applied in high-power laser gain medium, because of its flexible and optical controllability and special structure, which can overcome the design flaws of common optical fibers effectively. This paper studied the Yb3+ doping double-clad photonic crystal fiber. Through the theoretical analysis and numerical simulation, it optimized the structure design, drew the high doping concentration and double-clad fiber samples, analyzed the absorption and fluorescence spectra of fiber core material, and tested the optical fiber spectrum features, which can improve the performance of high power fiber laser.

Abstract: The traditional technology in production of doped fiber has disadvantage of low doping concentration, uneven distribution of refractive index, being difficult to produce large core diameter etc. This paper according to the demand of high-power ytterbium doped photonic crystal fiber laser, makes a research of producing methods to large mode area, Yb3+ doped photonic crystal fiber. Anhydrous doping nanometer particles are obtained by solution doping method, using plasma non-chemical vapor deposition method produce fiber core material, large mode area, ytterbium doped fiber sample is made and laser properties experiments has been done. By experiments it is found that at 2cm pre-end of the sample has violet light, Yb3+ doped fiber has laser operation.

Abstract: The facture behavior of a chromium (Cr) coating/ laser pre-quenched steel substrate system was investigated in this work. The results presented in this work show the crack density of the Cr coating on the laser pre-quenched steel substrate increases with the increase of the thermal fatigue times, and the failure process and modes of the Cr coating / laser pre-quenched steel substrate are the same as those presented in our previous work. However, the crack density of Cr coating on the pre-quenched substrate surface was much lower than that of the Cr coating on the original substrate surface under the same thermal fatigue loading. This indicates the Cr coating on the pre-quenched steel substrate has superior mechanical properties than that on the original steel substrate.

Abstract: Under the conditions of the presence of surfactants and ultrasonication, the use of different cerium salt, respectively, with carbonate under solid state chemistry reactions, the synthesis of nanorare earth metal complexes of cerium carbonate crystals was formed. The solid phase was characterized by powder X-ray diffraction (XRD) and electron diffraction (ED). The particle size, its distribution, and morphology of the prepared nanocrystallite were observed by transmission electron microscopy (TEM). The results show that particle sizes are relatively uniform, the morphology of the crystal is spherical, the average particle diameter is about 60 nm, and the yield rate is approximately 93.2%. Furthermore, during the synthesis, the solid-state reaction conditions including raw materials, matching proportion of reactants, additions of inert substance, addition of trace solvents, surfactants and porphyrization time, etc, all have some influence on the morphology, particle size and size distribution of the final products. During the synthesis of the cerium carbonate nanocrystallites, the solid state reaction conditions such as changing reactant, matching proportion of reactant, adding inert substance, joining a little solvent or surface active solvent and grinding at different times may influence morphology, particle size and the size distribution of final products.

Abstract: A detailed beneficiation test of fluorite ore with barite from Hunan area was studied. The grade of the fluorite in the crude ore is 56.47% and the barite is 17.32%, mainly gangue minerals is quartz. According to the properties of the ore, by comparing the results of various tests, we decided take the procession as follow: after the grade classification, coarse grain tailing by the jig, and then bulk flotation fluorite and barite ore, mixed flotation concentrate then float the fluorite and restrain the barite, the fine particle come into the shaking table to concentrate the barite fine particle concentration. Finally the grade of fluorite concentrate is 96.54% and recovery rate is 89.77%; the grade of barite concentrate is 88.78% and recovery rate is 97.46%. Then we achieved the good test indicator.

Abstract: The copper-iron ore has grades of 0.58% Cu and 42.14% Fe in Anhui. According to test on raw ore, it has the characteristics of close intergrowth and fine dissemination size, which belongs to a refractory ore. The copper oxide distributes mainly at the perimeter of copper sulfide. According to the characteristics of the structure, a flow sheet of rough grinding and flotation of inter-locked particles is taken. This process can recover copper effectively, leading to the recovery of Cu increase to 70.05%.A combined technological process of high intensity magnetic separation-gravity separation is used to hematite, which achieves an iron grade of 62.34% in the final concentrate and a recovery of 65.49%.

Abstract: The dynamic experiments about the conversion of CO₂ from simulated flue gas were carried out in a bubbling reactor containing a kind of adsorption with M dissolving in ethanol and water at atmospheric pressure. Based on the results of product analysis and electrode potentials, the reaction mechanism of CO₂ reduced by M was deduced. The results of dynamic experiments showed that the reaction order was 1.0, the rate constant was 5.91×10^-2 s^-1, and the apparent activation energy was 23.47 kJ·mol^-1.

Abstract: The effects of Fe content on the corrosion behavior of Al-Zn-In-Mg-Ti-Si sacrificial anode were investigated by the microstructure observation and electrochemical measurements in order to improve the dissolution feature and electrochemical properties. The results show that the current efficiency of Al-5Zn-0.02In-1Mg-0.05Ti-0.12Si-0.1Fe (wt.%) alloy corroded uniformly reaches 93 % in seawater. It presents the property of lower resistance and higher capacitance. While the Fe content exceeds 0.1 wt.%, the resistance of active dissolution increases gradually. The current efficiency falls down obviously. The results indicate that the electrochemical properties and dissolution feature can be improved significantly by suppressing Fe content under 0.1 wt.% in Al-Zn-In-Mg-Ti-Si alloy.

Abstract: The electrocatalytic oxidation of formaldehyde on Nickel-Poly (o-toluidine) - polyvinylalcohol modified glassy carbon electrode (Ni-P(OT)-PVA/GCE) was developed. This involves in situ electropolymerization of o-toluidine at GCE, which is following to the incorporation of Ni (II) to polymeric layer by immersion of modified electrode in 1.0 M nickel sulphate solution. The general electrochemical behavior was characterized by cyclic voltammetry and chronoamperometry methods in alkaline media. The results showed that the Ni-P(OT)-PVA/GCE system exhibits a significant electrocatalytic activity towards oxidation of formaldehyde. The effects of scan rate and formaldehyde concentration on the electrocatalytic oxidation of formaldehyde were also investigated at the surface of Ni-P(OT)-PVA/GCE.