Advanced Materials Research Vols. 311-313

Abstract: The application of nanosilica in coating of art paper and ink-jet paper is studied. The results show that when nanosilica is used in art paper coating, the dispersity and flowability of the art paper coating are excellent. The surface strength, smoothness and gloss of the paper coated with art paper coating with nanosilica are improved and its yellowing rate is decreased. When nanosilica is used in ink-jet paper coating, the dispersity of prepared ink-jet paper coating is of better, the coated paperboard with ink-jet paper coating with nanosilica is of ink transfer larger, K&N value higher and whiteness higher. The smoothness and gloss of paperboard coated with ink-jet paper coating with silica are improved. The combination application of more kinds of adhesives improves the print gloss of paperboard coated with ink-jet paper coating with silica.

Abstract: The properties of akaganeite (β-FeOOH) are affected by the coexisting ions and can be changed by doping various ions. Tin doped β-FeOOH nanorods were prepared using β-FeOOH nanorods as the precursor under hydrothermal conditions. The effect of tin ions on the thermal property of β-FeOOH was investigated. The doping of tin ions was confirmed by X-ray powder diffraction, energy dispersive spectroscopy, and atomic emission spectrometer analysis. The adsorption of tin ions on the surface of β-FeOOH could prevent the transformation from β-FeOOH nanorods to α-Fe₂O₃ in solution. Thermogravimetric analysis and differential thermal analysis showed they have different thermal decomposition temperatures. β-FeOOH nanorods were transformed into α-Fe₂O₃ particles at 400 °C. While tin doped β-FeOOH nanorods should be heated to 600 °C. Tin doped β-FeOOH nanorods showed higher thermal stability than that of β-FeOOH nanorods. The presence of tin ions is favor of the formation of rod like shape.

Abstract: In hardening stage, a model was used to study the plastic deformation behaviors of nanocrystalline materials. The material was considered as a composite of grain interior phase and grain boundary (GB) phase. The constitutive equations of the two phases were determined in term of their main deformation mechanisms. In softening stage, a shear band deformation mechanism and the corresponding constitutive relation were presented. Calculation results have shown that the predications fit well with experimental data. The investigation using the finite-element method (FEM) provided a direct insight into quantifying shear localization effect in nanocrystalline materials.

Abstract: We postulated a softening model involving grain rotation that results in diffusion-accommodated grain-boundary sliding. This numerical model was used to compute the proportion evolution of grains within shear bands and was also employed to predict the softening of nanocrystalline materials considering non-homogeneous plastic deformation due to shear bands. The effect of softening mechanism for total stress-strain relation and the grain size and mean maximum Schmid factor effect was also considered in our model.

Abstract: The performance of the dispersion of cobalt blue in organic solvent is studied. The influence of dispersant (type & dosage), pH value, and other dispersion parameters on the stability of cobalt blue dispersion system is tested which shows good stability and excellent dispersion performance with diethylamide glycol ether the solvent, complex formulation (M (KH550): M (KH560): M (A-842) = 1:1:2) the dispersant and 7 the pH value. The characteristics of dispersion system are evaluated through sedimentation experiment and measurement of article size distribution. The most steady dispersion system is formed through high speed shearing force and the size of cobalt blue in this system is about 300nm.

Abstract: Using non-equilibrium Green’s function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a triangle terarylene(open- and closed-ring forms) optical molecular switch. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device is discussed. Theoretical results show that the conductance of the closed-ring is 3-8 times larger than that of open-ring, which expect that this system can be one of good candidates for optical switches due to this unique advantage, and may have some potential applications in future molecular circuit.

Abstract: For nanocrystalline BaTiO₃ ceramics, the ferroelectric P-E hysteresis loop was measured with different impressing rate of field. The results are interesting for different grain size samples. Based on the combination of the theory of Avrami mode and the reorientation of polarization vector, the experimental results are analyzed. It is shown that the reorientation of polarization vector is the chief mechanism of hysteresis for large grain and the formation of new domain is important for samples of small grain size.

Abstract: Co-electrospinning has been one of the most important and viable methods to prepare microfibers with hollow structure. In the process of co-electrospinning, microfibers were formed from polymer solution or melt by the action of high voltage electric field. In this article, the compound Taylor cone, a major parameter determining success or failure to prepare the hollow microfibers, was studied and the patterns of compound cone were summarized. The microfibers with single, double and triplicate holes in the cross-section were fabricated successfully under the guide of these patterns. The morphology of hollow microfibers was observed by scanning electron microscope (SEM).

Abstract: A hierarchically porous zeolite ZSM-5 is prepared under hydrothermal conditions by using hexadecyltrimethoxysilane as inhibitor and template. The physical and acid properties of the hierarchically porous ZSM-5 are characterized by XRD, SEM, N2 physisorption and NH3-TPD techniques. Benzene alkylation with methanol is carried out with both conventional and hierarchically porous ZSM-5 in a fixed bed reactor. The creation of mesoporosity in zeolite ZSM-5 promotes benzene conversion and xylene selectivity with respect to conventional counterpart.

Abstract: NiWO₄ nanoparticles were successfully synthesized by a molten salt method at 270°C. The as-prepared powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and exhibited a pure phase NiWO₄ with about 50 nm in particle size and uniform nearly-spherical particle shape.