Advanced Materials Research Vols. 335-336

Abstract: Cu₂ZnSnS₄ (CZTS) film was prepared by screen printing process with the advantages of simple, high-effective and cost-effective. The annealing effects on the screen printed CZTS films were studied. It was found that the crystallinity of the CZTS can be effectively improved by the annealing process, whereas overlong annealing can also introduce defects to the CZTS. The bandgap value of the CZTS is about 1.4 eV. The short-circuit current density, open-circuit voltage, fill factor and conversion efficiency of the best solar cell with superstrate structure of Carbon/CZTS/In₂S₃/TiO₂/FTO glass (without using any vacuum conditions) are 6.20 mA/cm², 290 mV, 0.29 and 0.53%, respectively.

Abstract: Production of building materials is mostly energy consuming. In the sphere of insulation materials we mostly see rock wool based materials or foam-plastic materials whose production process is demanding from material aspect and raw materials aspect as well. At present the demand for thermal insulation materials has been growing globally. The thermal insulation materials form integral part of all constructions in civil engineering. The materials mainly fulfill the thermal insulating functions and also the sound-insulating one. The majority of thermal insulation materials are able to fulfill both of the functions simultaneously. The paper describes questions of thermal insulation materials development with good sound properties based on natural fibres that represent a quickly renewable source of raw materials coming from agriculture. The main advantage of the materials are mainly the local availability and simple renewability of the raw materials. In addition an easy recycling of the materials after their service life end in the building construction and last but not least also the connection of human friendly properties of organic materials with advanced product manufacture qualities of modern insulation materials.

Abstract: The Ion Beam Enhanced Deposited (IBED) lithium tantalate (LiTaO₃) thin film samples with Al/LiTaO₃/Pt electrode structure were prepared on the Pt/Ti/SiO₂/Si(100) and SiO₂/Si(100) substrate respectively. The crystallization, surface morphology, ferroelectric property, and fatigue property of the prepared samples with the different annealed processes were investigated. The XRD measured results show that the prepared samples have the polycrystal structure of LiTaO₃ with the preferred orientation of <012> and <104> located at the 2θ of 23.6⁰ and 32.7⁰ respectively. The SEM morphology analysis reveals the prepared film annealed at 550°C is uniform, smooth and crack-free on the surface and cross section. The ferroelectric property measured results show that the remanent polarization Pr of the samples annealed at different temperature almost increase with the electric field intensity stronger. The leakage current makes the hysteresis loop of the samples subjected to a strong measured electric filed difficult to appear the same saturation hysteresis loop as the single-crystal LiTaO₃. The prepared samples annealed at 550°C have a Pr value of 11.5μC/cm² when subjected to the electrical field of 400kV/cm. The breakdown voltage of the 587nm thick thin film sample is high as to 680 kV/cm. The fatigue property measured results show only 15.17% Pr drop of the prepared films annealed at 550°C appear after 5×1010 cycles polarized by the 10MHz sinusoidal signal with the peak-to-peak amplitude of 10 Volt. The ferroelectric properties of the prepared films meet the practical application requirements of charge response measurement of the LiTaO₃ infrared detector owe to the Pr of the prepared films annealed at different temperature large beyond 10μC/cm² when the prepared films subjected to a strong electric filed larger than 400 kV/cm. The experimental results also show that the surface morphology, the ferroelectric and fatigue properties of the IBED LiTaO₃ thin films are significant better than those of the Sol-Gel derived LiTaO₃ thin films.

Abstract: Making VPO catalyst in the condition of different concentrations of Phosphoric acid and the temperatures，determine the average valence of vanadium. with the method of Potassium permanganate-Ferrous ammonium sulfate, to investigate the effect of different concentration of phosphoric acid on the average valence of catalyst, under the different temperatures. The structure, composition, crystal, and the Particle size has been characterized by XRD and SEM. The results confirmed that compare with higher concentration of phosphoric acid，the catalyst that were made with lower concentration phosphoric acid had the low average valence, greater specific surface area, better crystallinity, and more compact structure.

Abstract: The extraction behavior of five rare earth ions (RE³⁺) was investigated in ionic liquid (IL) extraction system using 1-butyl-3-methyl-imidazolium hexafluorophosphate ionic liquid ([Bmim]PF₆) as extraction solvent and benzoyl acetone (HA) as extractant. The extraction percentage of RE³⁺ using [Bmim]PF₆ was less than 8% without HA. When sufficient HA was included in IL phase, the extraction percentage of RE³⁺ could be higher than 98%. The extracted species in the RE³⁺-[Bmim]PF₆-HA system was neutral REA₃ and the recovery of RE³⁺ extracted into [Bmim]PF6 can be achieved using the mixture of hydrazine hydrate and ethylenediamine tetraacetic acid (EDTA) as stripping agent. [Bmim]PF₆ can be recycled in the experiment.

Abstract: Co-carbonization properties of toluene soluble (TS) of coal tar pitch and waste polystyrene (WPS) were studied in a tube bomb to correlate the content of alkyl groups in the mesophase pitches with coefficient of thermal expansion (CTE) and anisotropic orientation. The alkyl contents, which were increased from 12.0% to 33.3% by adding WPS into TS, improved the properties of resultant needle coke in terms of optical texture and CTE value. The anisotropic indices of average length of vectors parallel to the CTE axis and average length of anisotropic unit vectors increased from 20.8 μm to 28.4 μm and 23.4 μm to 28.8 μm, respectively, and CTE value decreased from 0.8×10^-6 /°C to 0.1×10^-6 /°C. Due to the increasing alkyl groups, the lower viscosity of the carbonization system favored the development of flow texture and uniaxial orientation. And the sufficient gas evolution of good timing in co-carbonization forced the uniaxial arrangement of bulk mesophase molecules at the solidification stage.

Abstract: In the present paper, monodisperse poly(lactic acid) (PLA) microspheres (MS) containing the enrofloxacin (ENRO), were manufactured by using a modified solid in oil in water (S/O/W) emulsion solvent evaporation method. In order to prepare PLA microspheres with a higher drug loading efficiency by this modified technique, the test of stability and productivity of the primary emulsion was preliminary examined by change species or concentration of the oil-soluble surfactant and the ratio of water and organic solvent. Firstly, enrofloxacin polylactic acid microspheres (ENRO-PLA-MS) were producted, then the morphology and particle size distribution were estimated by scanning electron microscopy (SEM), its encapsulation efficiency and drug loading efficiency were assessed by High performance liquid chromatography (HPLC). In vivo conditions were simulated by an stable release buffer to obtain a detailed release and polymer degradation profile. Consequently, the ENRO-PLA-MS had a denser structure with a smooth, pore-free surface, the preparation of microspheres was simple, the prepared microspheres had excellent controlled drug release characteristics in vitro.

Abstract: Nickel films of varying thicknesses between 70 and 300 nm were deposited on glass substrates by RF sputtering and their broad (111) FCC peaks were identified by X-ray diffraction. The surface roughness and sub-micron grains were revealed by scanning electron microscopy. According to vibrating sample magnetometry, the films showed hysteresis loops with comparable coercive field and saturation field for the in-plane and perpendicular magnetizations. The increase in thickness substantially increased the magnetization and the squareness of the Ni films. The thickness can be classified into 2 regimes by the variation of squareness. The films are thinner than 200 nm showed the in-plane anisotropy whereas the perpendicular anisotropy was developed in the case of the thickness above 200 nm.

Abstract: We used solid acid and solid base we made ourselves prepared 5-hydroxymethylfurfural (5-HMF) from glucose. Researched on the effects of quality ratio of solid acid and solid base, substrate concentration, volume ratio of two phases, reaction temperature and reaction time on 5-HMF yield. Results were shown that the conditions quality ratio of solid acid and solid base was 3: 4, substrate concentration was 50%, volume ratio of water phase and organic phase was 1: 2, reaction temperature was 120 °C, time for 12 h were the best that 5-HMF yield reached 48.39%.

Abstract: In the present work, porous HA scaffolds with well controlled pore size, porosity and high compressive strength were prepared by aqueous gelcasting. PMMA beads with different size were used as the pore forming agent. The compositions, microstructure and properties of porous HA bioceramics were analyzed by XRD, SEM, Hg porosimetry etc. The mechanical properties were also tested. For scaffolds with the porosity as 70%, the average compressive strength was 11.9±1.7 MPa. Results showed that glecasting process can be used for the preparation of porous HA biomaterials with well controlled pore size and improved mechanical properties.