Applied Mechanics and Materials Vols. 401-403

Abstract: The effects of electric current, the altitude of the liquid outlet and liquid level change within crucible in direct-current electromagnetic pump (EMP) used to quantitative pouring of aluminum alloy on flow rate were studied. The results show that the effects of electric current on flow rate is affected by the hydraulic resistance; flow rate decrease with the increasing of the altitude of liquid outlet; when the output of aluminum alloy is large, the liquid level change within crucible have a significant impact on flow rate.

Abstract: The TiB₂ whiskers were fabricated in TiB₂/TiC_x composites by the in-situ synthesis process. The phase composition, thermodynamics, weight loss and lattice parameters of the obtained phases were studied. The obtained TiB₂ whiskers showed an aspect ratio of 10-20 and a diameter of 0.5-1.5 μm. The synthesized TiC was a non-stoichiometric phase with a lattice parameter of 4.274 Å. Most of the whiskers had the cylinder shape, whereas, a few whiskers showed a bead-necklace morphology. The growth mechanisms of TiB₂ whiskers were governed by the solid-liquid-solid (S-L-S) mechanism and the particle-to-particle connection mechanism.

Abstract: The CuCr25 alloys were prepared by spray forming technology, and effect of process parameters on the deposit was studied. The microstructure of CuCr25 alloy prepared by spray forming was studied, and the size of chromium particles was 3-10μm. It is fond that spray-deposited CuCr25 alloys were hot forged and hot isostatically pressed to full densification,and the size of chromium particles was increased little after being hold at 1070°C for 60mins. Conclusions were drawn from the researching results that spray forming was an ideal method to prepare CuCr25 alloys with fine chromium precipitates and homogeneous dispersion. After hot forging and hot isostatic pressing, the size of chromium particles was increased to 10-15μm. the density of the CuCr25 alloy could be 99%.

Abstract: Based on the experiment of reciprocating grinding and in accordance with Jaeger moving heat source theory and the triangle model of the heat source, this paper established temperature filed of grinding-hardening machine and conducted numerical calculation with the temperature filed of grinding by the software ANSYS. Then it predicated the grinding-hardened layers depth in accordance with the results of numerical calculation, and compared with the experimental results to verify the rationality of the simulation results.

Abstract: The lattice parameters, phase transition, and thermodynamic properties of OsN₂ in pyrite and fluorite structure are investigated by first-principles calculations. The pressure and temperature induced phase transitions of OsN₂ from fluorite structure to pyrite structure have been obtained. It is found that the transition pressure of OsN₂ at zero temperature is 158.2 GPa, and there exists no transition temperature. In addition, the thermal expansion, the Debye temperature, and the Grüneisen parameter in diverse pressures and temperatures about these two structures have also been obtained. Key words: transition phase; thermodynamic properties; OsN₂ PACS numbers: 71.15.Mb, 64.70.Kb

Abstract: Polyaniline (PANI) nanotubes were synthesized separately using amino acetic acid (AA), ethylenediamine tetraacetic acid (EDTA), oxalic acid (OA) as dopant and ammonium persulfate (APS) as oxidant by a self-assembly method. SEM, TEM,FTIR and X-ray diffraction (XRD) and applying the 4 probes method characterized the morphology, structure and property of the product. It was found that nanotubes morphology were synthesized when the [Aci/[A ratio is 1:2.The room template conductivity of the products were studied.

Abstract: Ferrocenecarboxaldehyde (FcCHO) was covalently bound onto the multi-wall carbon nanotubes functionalized with amino groups (AMWNTs) to achieve Fc-AMWNTs conjugate. The cyclic voltammetry were used to characterize the nanocomposites. Here, Fc-AMWNTs were applied to construct glucose biosensors with IO4--oxidized glucose oxidase (IO4--oxidized GOx) through the covalent assembly method without any cross-linker. The presence of both ferrocene as mediator of electron transfer and MWNTs as conductor enhanced greatly the electrocatalytic response toward the glucose. Furthermore, our enzyme electrodes also showed remarkable stability due to the covalent interaction between the Fc-AMWNTs and the GOx.

Abstract: High-elasticity and high-modulus tennis rubber was manufactured mainly from NR and trans-1, 4-polyisoprene. The optimizing formula of rubber is: NR 82, TPI 18, Silica White 25, ZnO 10, Stearic Acid 1.5, Magnesium Carbonate 10, Antioxidant 1.5, Coupling Agent Si-693, Sulfur 4.5, Accelerator DM0.7, Accelerator D0.5. The tennis made of such optimized rubber can satisfy the industry standards.

Abstract: Nanosized Fe₃O₄ particles were prepared in glycol medium through a solvothermal method and the morphologies, structures, surface properties, and magnetism of the samples were characterized by SEM, XRD, FTIR absorption spectra and VSM. The experimental results show that the nanoparticle has a typical diameter of ca. 20 nm. The Fe₃O₄ nanoparticle diameters increased with increase of PEG content and PEG molecular weight under the case of other unchanged reaction conditions. The XRD pattern confirms that the Fe₃O₄ nanoparticles belong to cubic structure. The FTIR results indicate that the surface of the Fe₃O₄ nanoparticles are coated organic matter. Magnetic investigation reveals that the Fe₃O₄ nanoparticles have higher saturation magnetization and negligible coercivity at room temperature.

Abstract: Using the main raw material of fly ash, metal scrap and waste industrial acid, with the activating method of specific self-activator ,can prepare poly-ferric-aluminum-silicate(PFAS) flocculant of inorganic polymeric coagulates. Specific activator can effectively open the Si-Al bond in the fly-ash, greatly enhance the leaching rate of each element by adding a special activator (M), the added amount of M: SiO2 = 1:3, activation time of 1 hour, activation temperature to 900 °C, get the original product, on 65 °C with turbid acid to stir and leach, leaching time is 2 hours, get the best rate of leaching. By Controlling Molar ratio of (Al + Fe) and Si 1:1, Silicic acid polymerization pH 1.7, by choosing the appropriate amounts of flocculants and flocculation time ,can get the very good flocculation function, the light transmission rate of the handling-water may amount to more than 92.7%.