Advanced Materials Research Vols. 554-556

Abstract: A first principles calculation method was used to investigate the site preference of Ruthenium (Ru) at the γ/γ′ interface in Ni-based single-crystal superalloys. The calculation results show that the addition of Ru can decrease the total energy and the binding energy of γ/γ′ interface, which may result in an improved microstructure stability of Ni-based single-crystal superalloys. Moreover, by calculation, it is also found that Ru can stabilize both γ and γ′ phases and have a preference for Ni site at the coherent γ/γ′ interface. When Ru substitutes the central Ni at the γ/γ′ interface, a reverse partitioning of W, Re and Cr occurs; while the partitioning behavior of Mo is not affected. The influence of Ru on the partitioning behavior of W, Re and Cr in γ′-Ni3Al was studied by Dmol3 calculation as well. The calculation results show that W, Re and Cr have a preference for Ni site in γ′- Ni3Al with Ru alloying. When Ru substitutes the central Ni atom, the site preference of W, Re and Cr varies accordingly. Furthermore, electronic structure analysis of γ/γ′ interface and γ′-Ni3Al in terms of Mulliken population and partial density of states (PDOS) was performed to understand the alloying mechanism of Ru in Ni-based single-crystal superalloys. The results show that the strengthening effect of Ru alloying is mainly due to the reduction in binding energy of Ru as well as a p-orbital hybridization between Ru and the host atoms.

Abstract: 3-10％(wt) Polyvinyl pyrrolidone (PVP) was mixed with PA6 through the twin-screw extruder, a new type of high hygroscopic nylon resins can be obtained. With the increasing addition of PVP the crystalline state of PA6 changes from γ to α phase. The intermolecular hydrogen bond exists between PVP and PA6. The FTIR and WAXD analysis can approve the existence of the intermolecular hydrogen bond and the change of the PA6 crystalline state.

Abstract: The objectives of this study were to prepare leadless crystalline glazes from iron oxide by using low temperature firing (1,100°C) and to study the effect of concentration of iron oxide on the phase composition of the glaze raw materials on phase transformation in leadless iron oxide crystalline glaze. The crystalline phases were investigated by using the DTA, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The composition of the glaze raw materials compose of nepheline syenite, colemanite, pottery stone, bentonite, ZnO, Li₂CO₃, SiO_{Subscript text}2 and 10, 15 and 20%(w/w) iron oxide (Fe₂O₃). The glaze raw materials were ground for homogeneous mixtures by ball milling for 24h. The average particle size of the mixture was 3.86 µm. The glaze bodies were carried to firing at 1,100°C at the heating rate of 2°C/min and soaking for 0.5h. Then, the glaze bodies were cooled at the cooling rate of 1°C/min and maintained at 1,080°C for 3h and then maintained at 980°C for 1h, respectively. From the experiment results, it was found that the crystallization temperatures (Tc) of franklinite (ZnFe₂O₄) and anorthite (CaAl₂Si₂O₈) depend on the concentration of iron oxide content.

Abstract: Although lasing has been observed in the solid state for numerous organic molecules emitting at visible wavelengths, this is few case in the infrared. We show amplified spontaneous emission (ASE) in the near infrared (913-930 nm) from the layer of a cyanine dye-doped 4-cyano-4'-pentylbiphenyl (5CB) for laser power above 0.08 GW/cm², the layer was prepared with the solution of 1,1',3,3,3',3'- hexamethyl-4,4',5,5'-di-benzo-2,2'-indotricarbocyanine perchlorate (NK-2014) dissolved in 5CB. Oriented NK-2014 molecules in nematic liquid crystal (NLC) must have very high amplified spontaneous emission efficiency.

Abstract: The supramolecular interaction of BPO and ß-CD has been studied by spectrophtometry. The mechanism of the inclusion was studied. The results showed that ß-CD react with BPO to form a 2:1 or 1:1 host-guest complex.The ß-CD reacts with benzoic acid to form a 1:1 host-guest complex after the BPO was reduced by hydroxyl ammonium chloride.Based on the enhancement of the absorbance of BPO produced through complex formation, a spectrophotometric method for determination BPO in bulk aqueous solution in the presence of ß-CD was developed. A linear relationship between the absorbance and BPO concentration was obtained in the range of 0.2～50 μg.ml^-1. The proposed method was used to determine the BPO in the flour with satisfactory results. The principal advantage of the proposed method is its excellent selectivity based on molecule recognition of ß-CD and simple.

Abstract: A chemical bond simulation was proposed to quantitatively calculate the growth rate from the kinetic model of the crystal-solution interface. When this approach was applied to the cases of potassium dihydrogen phosphate (KDP) crystals grown from the solution with different surpersaturation, the growth behaviors of KDP crystals were predicted and the calculated results were consistent with the experimental data. These results demonstrate that regulating the distribution of the chemical bonds between the crystal and solution interfaces can effectively control the crystal morphology. Seeding experiments with the chemical bond simulation may have significant potential towards the development of shape-controlled growth with defined conditions.

Abstract: Morphology and crystal phase of calcium carbonate, which formed with the presence of Mg²⁺, were characterized by SEM and XRD. The effect of Mg²⁺ on crystallization and crystal phase of calcium carbonate was studied. The results showed that the crystal phase of calcium carbonate were mainly calcite and aragonite and the content of aragonite was higher after adding Mg²⁺ to the blank solution. With the increase of Mg²⁺ concentration, the content of aragonite increased. The calcium carbonate crystals grain became more fine and the content of aragonite was higher by synergistic treatment between Mg²⁺ and magnetic field. There was a strong inhibitory effect on calcite when the concentration of Mg²⁺ was more than 0.50mmol.L-1. The calcite could be transformed into aragonite in the presence of Mg²⁺ in solution.

Abstract: The compound of perylene-3,4,9,10-tetracarboxylic acid (PTCA) has been synthesized and characterized. By varying the concentration, it can be used to modulate the supramolecular self-assembly morphologies. Atom force microscopy (AFM) images show that the nano-layer structure will be obtained in relatively high concentration. This structure mainly depends on the intermolecular hydrogen-bonding and π–π stacking interactions.

Abstract: A new HBC derivative HBC-C₁₇ containing 6 odd-carbon alkyl chains surrounding the hexabenzocoronene core was synthesized, and investigated as discotic liquid crystal along with HBC-C₁₃ and HBC-C₁₅. The thermal behaviors have been investigated by using differential scanning calorimetry (DSC). And mesomorphic phase behavior of HBC-C₁₇ was observed by polarizing optical microscopy (POM). A remarkable variation in the phase transition temperatures was observed for these three HBC derivatives (HBC-C₁₃, HBC-C₁₅ and HBC-C₁₇). Moreover, the mesomorphism of these HBC derivatives can be compared with HBC-C₁₂, HBC-C₁₄ and other HBCs with even carbon alkyl chains, meanwhile the relationship between the length of substitutes and thermal properties of HBCs is also studied.