Applied Mechanics and Materials Vols. 130-134

Abstract: Numerical calculation model with compound insulation of transient electric field is given. The insulation is more prominent due to complication for voltage applied on valve side winding of the converter transformer. So the simplied structure for electric calculation on the valve side winding of the converter transformer is established. The electric field distribution characteristics on the valve side winding of the converter transformer is analyzed and electric fields in different resistivity and permittivity are calculated under AC high voltage, DC high voltage, AC superimposed DC voltage, polarity reversal voltage. The maximum electric field intensity is calculated and analyzed under kinds of high voltage. Some important influence factors for electric field distribution are also discussed in this paper.

Abstract: Considering the non-linear property of the magneto-rheological damper and the low accuracy of the traditional fuzzy control, this paper introduces a semi-active magneto-rheological damper controller which is based on the improved variable universe fuzzy control strategy and conducts a simulation of it. Next, it analyzes the damping effect of the passive suspension and the semi-active suspension. As indicated by the results, the use of the advanced variable universe fuzzy control strategy can effectively improve the ride and comfort of an automobile, and it serves as a reference for the further theoretical researches and sample vehicle experiments in the future.

Abstract: In order to improve the quality of image transmission, this paper puts forward a box shielding method that could eliminate electromagnetic interference signal on image transmission equipments. At first, this paper analyzes the shielding effectiveness of electromagnetic interference, selects the qualified shielding material and designs the structure. After that, it analyzes the descending of shielding effectiveness in the operational system, and improves the equipments shielding effectiveness by means of the electromagnetic compatibility design that accords with electromagnetic compatibility norms. At last, through the EMI radiometry, this paper confirms that the equipments are in accordance with the design requirements of electromagnetic compatibility norms.

Abstract: Based on the in-depth study of traditional weft insertion mechanism, the electromagnetic technology was introduced into the textile machinery, a new weft insertion mechanism was designed whose shuttle was moved fast in the shed by the electromagnetic force. The electromagnetic force was generated by electromagnetic coils. Meanwhile, the PLC control system which control the new electromagnetic weft insertion mechanism was devised to achieve the high speed of the shuttle.

Abstract: Using GGA+U (U_Co =2.1eV, U_Fe=2.5eV) scheme based on the density functional theory (DFT), we investigate the electronic structure, magnetism and half-metallic stability of Ga-doped Heusler compound Co₂FeSi. We find that the lattice constants and total magnetic moments in per unit respectively obey the Vegard’s rule and the Slater-Pauling rule well. The most stable half-metallicity occurs at doping concentration x=0.5 due to the Fermi level is situated slightly above the middle of the spin-down gap. Our studies also indicate that the RKKY-type exchange mechanism plays a dominating role in determining the magnetism of HMFs.

Abstract: The nitrogen dopants can convert the nonmagnetic ZnO into a ferromagnet based on first-principle calculations. The formation of oxygen substituted with nitrogen on the surface is much easier than that inside nanowire. Calculation results indicate per N dopant can produce a total moment of 1.00 u_B in the nitrogen-doped ZnO, the magnetic moments mainly come from the unpaired 2p orbit split of N atom. Our theoretical study not only demonstrates the ZnO nanowire can be magnetic even without transition-metal doping, but also suggests that introducing N dopant is an effective way to fabricate low-dimensional magnetic ZnO nanostrucres.

Abstract: The electronic and magnetic properties of the boron nitride (BN) sheets with different chemical decoration are investigated using the first-principles plane-wave calculations within density functional theory (DFT). It is demonstrated that bare BN sheets are nonmagnetic semiconductors with wide band gaps, and a metallic–semiconducting–half-metallic transition with a nonmagnetic– magnetic transfer can be realized through chemical decoration. Specifically, BN sheets modified by H with zigzag configuration still behave as semiconductors, while with armchair configuration are metallic. Nevertheless, decorating BN sheets by F or OH with zigzag configuration reveal half-metallic properties, then with armchair configuration present spin-polarized semiconducting characteristics. The results may be of importance in designing BN-based electronic devices for nanoelectronic applications.

Abstract: This article dealt with the effect of phosphorylated peptides and peptides onto hydroxyapatite (HAP) biomaterials by considering their influence when they were present at the synthetic HAP interface. The adsorption isotherms adequately fitted the Langmuir shape, and from the comparision between two different adsorbates, the results of the investigation indicated that the phosphate group greatly enhanced the adsorption affinity. The results obtained layed the solid foundation for further research on the regulating function of phosphorylated amino acids with hydroxyapatite biological composites.

Abstract: Sepiolite/poly (sodium acrylate-acrylamide) composite was synthesized by using inverse suspending polymerization method under different dispersant content, neutralization degree and ratio of monomer with orthogonal experiments. The surface morphology, structure and humidity controlling properties of composite were observed and determined. The results show that sepiolite/ poly (sodium acrylate-acrylamide) composite is in a fine particle with rough surface. During the polymerization process, acrylate and acrylamide monomer is grafted with hydroxyl on the surface of sepiolite and then intercalated successfully into the silica layers of sepiolite. The impact of three factors on the humidity controlling behavior of composites increases by the order of dispersant content, ratio of monomer and neutralization degree. The optimum preparation parameters are dispersant content of 10%, neutralization degree of 85% and ratio of monomer 2:1.

Abstract: Tetragonal and hexagonal calcium zincate as an active material in Zn/Ni secondary battery has been successfully prepared with precipitation transformation method by isothermal in the reasonable concentration of KOH as base solution for the first time. The chemical composition of Ca [Zn (OH)₃]₂•2H₂O was confirmed by X-ray powder diffraction pattern 、TG-DSC and infrared spectroscopy. These results all show that perfect crystal shape of either regular tetragonal or hexagonal calcium zincate (regardless of crystal size) should always have the same chemical expression of Ca [Zn (OH)₃]₂•2H₂O as its form; and incomplete crystal shape of calcium zincate prepared in different conditions , their chemical expression may be the form of Ca [Zn (OH)₃]₂•nH₂O(n=1~2).