Advanced Materials Research Vols. 989-994

Abstract: The spectroscopic behavior of a photochromic compound 5, 11, 17, 23-tetra-tert-but yl-25, 27-bis (1’,3’,3’-trimethyl-6-nitrospiro-[2-H-1-benzopyran-2,2’-indoline]-8-methoxycarbonylmethoxy)-26,28-dihydroxycalix [4] arene (1) and its complex with lanthanum nitrate was described. Compound 1 has typical photochromic properties for its two spirobenzopyran groups. The complexation spectroscopic behavior has been investigated in anhydrous acetonitrile by UV-vis, fluorescence spectra and ESR spectra. The results obtained proved the formation of complexes and indicated that the spectroscopic behavior of the supramolecular system could be regulated by light. The system might be used as on-off switches.

Abstract: use the sol-thermal method to synthesis nanoparticle TiO2 which is well developed, small diameter and good dispersion. XRD and BET methods were used to analyze the crystal structure and specific surface area. Under nature solar light, the photodegradation activity of TiO₂ is tested. The results show that the TiO₂ sample displayed better photodegradation activity than P25 under solar irradiation.

Abstract: Mn-doped TiO₂ nanocrystal photocatalysts were prepared by the sol-gel method using MnSO₄·H₂O as manganese source. The catalysts were characterized by XRD, SEM, EPR, UV-Vis, their photocatalytic activity for methylene blue (MB) degradation was investigated. The results showed that Mn was doped into the crystal lattice of TiO₂, and had no influence on TiO₂ crystal structure; the size of TiO₂ nanoparticle gradually decreased with Mn doping concentration increasing. The Mn-doped TiO₂ catalysts have enhanced absorption in the visible light region, and its visible light absorptivity increased with Mn doping concentration increasing. The UV-Vis showed the Mn-doped TiO₂ showed higher photocatalytic activity than the undoped TiO₂ for methylene blue degradation under visible light irradiation. It is also found that the MB photodegradation rate of Mn-doped TiO₂ improved by 46% than that of the undoped TiO₂.

Abstract: The corrosion inhibition of mild steel in 5.0 M HCl by 1–phenylaminomethyl-benzimidazo -le (PMB) was studied by gravimetric and potentiodynamic polarization methods. Inhibition efficiency of PMB increased with increase in the concentration of inhibitor and decreased with the increase in temperature. PMB acts as anodic-type inhibitor for mild steel. The adsorption of PMB on mild steel surface obeys the Langmuir adsorption isotherm.

Abstract: The nanosized magnesium hydroxide is a valuable intermediate for chemical industry materials. This review covers the preparation methods of nanosized magnesium hydroxide using concentrated seawater or brine as raw material, including alkaline method, calcium method, ammonia method and other new methods. Additionally, the development trend of preparing nanosized magnesium hydroxide from concentrated seawater or brine was analyzed.

Abstract: In this paper, the Back-Propagation neural network (BP network) and the establishment of the AZ61 magnesium alloy high temperature constitutive model and test data obtained for training the neural network, after training the neural network to become a knowledge-based constitutive model formed AZ61 magnesium alloy flow stress and dynamic recrystallization of the neural network model tested by the neural network model with traditional regression methods predict contrast, results showed that the higher the accuracy of the neural network model for dealing with a large number of test data to establish the constitutive relations of materials with high stress and promotion of value.

Abstract: In this paper, rigid-plastic finite element simulation software Marc / Auto-forge reflect compression AZ61B magnesium alloy case. Simulation results show that the stress, strain and temperature distribution within the sample is uneven, uneven distribution affect the organization, and with the changes in the deformation process and calculation results with the experimental data exactly. The finite element method can be used in the actual production forecast after tissue deformation components, optimization of process parameters to control the quality of the finished piece.

Abstract: Because of the characteristics of both one dimensional nanostructure and excellent physical and chemical properties, the kinds of novel nanomaterials-tungsten carbide nanowires, have important academic significance and practical meaning. The research development of one-dimensional nanostructured tungsten carbide is reviewed. The production methods of one-dimensional nanostructured tungsten carbide, such as nanotubes, nanorods, nanowires and nanoneedles by thermal decomposition technique, vapour deposition technique, magnetron sputtering technique, Eruptive heating technique and template technique respectively are systematically introduced. This paper summarizes the growth mechanisms and the problems involved in the existing synthesis methods. The research tendency is also forecasted.

Abstract: An approach to the scale-up of grooved nanofibers via a flat off-centered core-shell structure spinneret has been developed in this study. The spinneret with a flat surface involves shell-holes and off-centered core-needles. The position of the core-needle in the hole and the electrospinning process do influence the formation and structure of the grooved nanofibers. The production rate of the core-shell nanofibers can be enhanced by increasing the hole and needle number of the spinneret. This novel design is expected to provide a promising method towards the massive production of grooved nanofibers.

Abstract: Multiwalled carbon nanotube (MWCNT) was subjected a copolymerization reaction with 4, 6-diaminoresorcinol salt (DAR•2HCl) and terephthalic acid (TA) in polyphosphoric acid (PPA) by Friedel-Crafts acylation reaction without any acid treatment or modification. The structure and morphology of the as-prepared poly (p-phenylene benzobisoxazole) (PBO)/MWCNT nanocomposites were characterized by X-ray diffraction (XRD) and scanning electronic microscope (SEM). The SEM images indicated that MWCNTs can disperse in PBO matrix uniformly without agglomeration and MWCNTs have been introduced into PBO matrix by covalent bonding via Friedel-Crafts acylation between MWCNTs and TA.