Advanced Materials Research Vols. 197-198

Abstract: For getting higher quality and sphere shape product Co₃O₄.The article studies precursor baked temperature,baked time, baked temperature route, Baked condition affecting on d_apparent, then points out obtaining sphere shape Co₃O₄ technology. Test shows if the practice is accorded to the technology strictly,demanding standard Co₃O₄ can be obtained.

Abstract: A novel photochromic diarylethene based on thiophene and a six-membered aryl moieties 1-[(2-methyl-5-(p-methylphenyl)-3-thienyl)]-2-[(2-trifluoromethylphenyl)]perfluorocyclopentene(1a) has been synthesized. Its properties, including photochromic behavior and fluorescent properties, have been investigated. The results showed that this compound exhibited reversible photochromism, changing from colorless to purple after irradiation with UV light both in solution and in PMMA amorphous film. The fluorescence intensity decreased along with the increase of solution concentration. The diarylethene exhibited relatively strong fluorescence at different solvent.

Abstract: A new photochromic diarylethene compound 1-(2, 4-dimethyl-thiazole-3-yl)-2- [2-methyl -5-(3-cyanophenyl)-3-thienyl]perfluorocyclopentene 1a was synthesized and its photochromic properties, such as phoochromism, fluorescence switch and optical recording were investigated detail. The result showed that this diarylethene compound showed good reversible photochromism. Upon irradiated UV light it changes from colorless to orange both in solution and in PMMA amorphous film. In addition, the fluorescence spectra of diarylethene 1a were nearly quenched with the concentration increased. Finally, using diarylethene 1c as recording medium, polarization optical recording was carried out successfully.

Abstract: Spinel-perovskite multiferroics of NiFe₂O₄/BiFeO₃ nanoparticles were prepared by modified Pechini method. The structure and morphology of the composites were examined by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the composites consisted of spinel NiFe₂O₄ and perovskite BiFeO₃ after annealed at 700°C for 2h, and the particle size ranges from 40 to 100nm. VSM and ME results indicated that the nanocomposites exhibited both tuning magnetic properties and a ME effect. The ME effect of the nanocomposites strongly depended on the magnetic bias and magnetic field frequency.

Abstract: We researched the shock-cushioning performance of different shape Aluminum foam-polyurethane composite material, which is a combination material with the polyurethane as base body and the aluminum foam as reinforcing body. The volume proportion of the filling aluminum foam was 12.15%. The structural shape of the composite material constructure were column, equilateral triangle and square, respectively. And the acceleration speed was 7800g. The paper established Aluminum foam-polyurethane shock-cushioning model, and analyzed the stress of the model, gained the distortion of different models, and analyzed shock-cushioning capability of the models. Results showed that the shock-cushioning performance were equilateral triangle, column and square from high to low.

Abstract: Tl₂Ba₂CaCu₂O₈ (Tl-2212) films were prepared on r-cut sapphire substrates buffered with CeO₂ by dc magnetron sputtering and post-annealing method. The in situ two-temperature process was used to grow CeO₂ buffer layers. XRD and AFM measurements showed that CeO₂ films deposited at temperature of 370-470°C were excellent c-axis orientation and had smooth surface. SEM observations demonstrated that the Tl-2212 films’ surface morphology was changed from condensing crystal structure to plate-like structure when the CeO₂ deposition temperature was increased. The best Tl-2212 film’s critical temperature T_c can reach to 108.3 K, and critical current density J_c obtained at 5.33 MA/cm² (77 K, 0 T).

Abstract: Three different chiral ionic liquids, chloride (R)-(+)-β-(1-methyl-imidazole)–propio-nate, (R)-(+)-β-(1-methyl-imidazole)-propionate terafluoroborate and hexafluorophosphate, weresuccessfully synthesized via the nucleophilic substitution reaction and the anion metathesis reaction, with (S)-(-)-2-chloro-propionic acid as the chiral source. Structures of the chiral io-nic liquids have been characterized by the infrared spectroscopy, nuclear magnetic resonancespectroscopy and quantum chemical structure optimization method. These new ionic materia-ls can be used as building blocks for the synthesis of ionic liquids.

Abstract: A novel chelating resin, crosslinking polystyrene-supported glucosamine (PS-GA), was prepared and its static adsorption properties for Ag(Ⅰ) were studied. The results indicated that this resin had excellent adsorption capacity for Ag(Ⅰ). The adsorption dynamics indicated that adsorption was controlled by the liquid film diffusion and the apparent activation energy Ea was 11.83 kJ/mol. Both Langmuir model and Freundlich model could describe the adsorption isothermal process of Ag(Ⅰ), and ∆G, ∆H, ∆S values were calculated. Increasing the temperature was beneficial to adsorption. The chelating resin can be easily regenerated by 2% thiourea in 0.1 mol/L HNO3 with higher effectiveness. Five adsorption–desorption cycles demonstrated that this resin was suitable for repeated use without considerable change in adsorption capacity.

Abstract: By the addition of flake Cu particles to polyurethane the infrared emissivity of polymers can be decreased significantly. In this work, the flake copper particles were prepared by solution phase reduction method. The PU pre-polymer was prepared by a typical method which using polyether polyol N220 and tolylene diisocyanate (TDI). Cu/Polyurethane composite was prepared by using incorporation method. The structure and morphology of Cu particles and Cu/Polyurethane composite were characterized by Fourier transform infrared spectrum spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD) and Energy Dispersive X-ray Detector (EDS). Moreover, the effects of copper particles content on infrared emissivity properties of composite were studied too. The results show that the flake Cu particles were prepared and dispersed well in polyurethane matrix. The infrared emissivity of composite was decreased with increasing particles loading. The composites get lowest infrared emissivity 0.546 when the loading of fillers increased to 20%.

Abstract: Structural, electronic and optical properties of 2H-CuAlO₂ were computed, using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory (DFT). The equilibrium lattice parameters, band structure, densities of states (DOS) and charge densities of 2H-CuAlO₂ have been obtained. The equilibrium lattice parameters, band structure and DOS are found to be in good agreement with the available experimental and calculational values. The charge densities and the chemical bonding of 2H-CuAlO₂ are analyzed, which show that bonding between Cu and O is mainly covalent due to Cu 3d and O 2p hybridization and that bonding between Al and O is mainly ionic. The complex dielectric function, refractive index and absorption coefficient of 2H-CuAlO₂ have been predicted. The calculated static dielectric constant and static refractive index of 2H-CuAlO₂ is 7.1 and 2.66, respectively.