Advanced Materials Research Vols. 557-559

Abstract: Zinc oxide coated hollow glass beads were prepared by Chemical package method with ZnSO₄٠7H₂O,NH₄HCO₃ and hollow glass beads as raw materials, and they were characterized with UV/VIS spectrophotometer,SEM, and the heat insulation properties was detected by the homemade device. The experiment results shown that the near-infrared reflectivity of zinc oxide coated hollow glass beads was 45.1% better than the 12.5% of hollow glass beads, and it has good heat insulation properties.

Abstract: P-doped ZnO thin films were prepared on different Si substrates by RF magnetron sputtering in Ar and O₂ mixed atmosphere. The P-doped ZnO films were changed from n-type to p-type by phosphorus diffusing from the n-Si substrates with higher phosphorus concentration into the ZnO films during depositing. The crystal structure of the ZnO films was examined by X-ray diffraction and confirmed to belong to wurtzite and highly c-axis oriented primarily perpendicular to the substrate. The Hall effect measurement results show that the corresponding hole concentration and risistivity of the P-doped ZnO film was 8.982×10¹⁷ cm^-3 and 1.489 Ω•cm respectively. This reveals that the P-doped ZnO thin film is really p-type behavior.

Abstract: The charge/discharge properties of commercial metal hydride alloy powder (MmNi_3.81Mn_0.41Al_0.19Co_0.76) is improved and modified by electroless plating nickel. The effect of concentration of reducing agent (Cr), concentration of complex agent (C_c), reaction temperature (T), reaction time (t), and the amounts of MH powder per volume (CMH) on the utilization of the modified MH alloy used as the negative electrode of Ni/MH battery is systematically studied. The utilization of modified MH alloy is mainly affected by Cr, Cc and t. The utilizations of MH alloys modified with condtions of T = 70 oC, t = 90 min, Cr = 20 g l^-1, Cc = 20 g l^-1 and CMH = 20 g l^-1, respectively, are obtained to be 92.3, 64.7 and 23.6% at discharging rate of 1, 4, and 10 C. The utilizations of modified MH alloy are increased by 15.5, 45.6 and 19.8% compared with the pristine MH alloy for discharging rates of 1, 4 and 10 C, respectively.

Abstract: Surface properties and Ni(II) adsorption characteristics of HA-vermiculite were investigated and compared with those of vermiculite. The cation exchange capacity (CEC), pH at zero point of charge (pHZPC), and surface charge at pH 6.5 and surface fractal dimension of HA-vermiculite were 44.69 cmol/kg, pH 2.57, -0.418 mmol/g, and 2.45, respectively. Compared to vermiculite, the CEC, surface negative charge and surface fractal dimension of HA-vermiculite increased, and the pHZPC of HA-vermiculite decreased. The adsorption data for Ni(II) by HA-vermiculite could be fitted by Langmuir isotherm (R2 =0.982) and also by Freundlich isotherm (R2 =0.987). At pH 6.5, the Langmuir maximum adsorption capacities for Ni(II) of vermiculite and HA-vermiculite were 11.86 and 19.41 mg/g, respectively.

Abstract: Microarc oxidation coatings were prepared on the surface of AZ31 magnesium alloy profiles. Oxidation time of the coatings was between 5min-10min. The phase structure, surface morphology and corrosion resistance of the coatings were investigated using SEM, XRD, copper sulfate spot test and polarization curve test. The results indicate: the main phase compositions of the microarc oxidation coatings are MgO, Mg₂SiO₄ and MgSiO₃; with increasing pulse voltage, the micropore diameter of the coating surface becomes larger, the micropore number reduces and the coating surface roughness increases; the corrosion current density of magnesium alloy reduces significantly after microarc oxidation treatment. The pulse voltage of microarc oxidation should be controlled between 240V-360V to obtain the best corrosion resistance.

Abstract: Titanium Nitride (TiN) thin film was deposited on β-type Ti-15Mo-3Nb-3Al-0.2Si alloy plates by RF magnetron sputtering method. The effect of nitrogen flow rate on the structure and properties of the TiN thin films were studied. The preferred orientation of TiN thin films changed from (111) to (200) as the nitrogen flow rate increased due to the effect of the kinetic energy of the bombarding particles. The coating thickness was found to decrease with increasing nitrogen concentration, which also favors (200) orientation with increasing nitrogen flow rate. With increase of nitrogen flow, the morphology of the TiN thin films films changed from characteristic pyramidal shaped grains to columnar-shaped grains. The roughness analysis of the coating shows that the average roughness of the coating decreased with increasing nitrogen flow rate. The increase of hardness with increasing nitrogen flow rate is attributed to the decrease in grain size.

Abstract: The concept of storing energy in TiO₂ when it was illuminated with light and using the catalyst when there was no light was tested for the first time. Ni(OH)₂ was incorporated into TiO₂ for the energy storage purpose. Ni(OH)₂ was subjected to three different temperatures (300 – 500°C) before the incorporation. NiO/TiO₂ bilayer films were prepared with spin-coating method. The films were tested for its electrochemical and photoelectrochemical properties in 1 M NaOH. The NiO/TiO2 film prepared with Ni(OH)₂ calcined at 300°C showed energy storage potential. The catalysts were then investigated for their catalytic activity in the photocatalytic degradation of acid orange 7 (AO7). The experiments were carried out in a batch reactor containing 500 ml of 20 ppm AO7 and 0.2 g NiO/TiO₂ bilayer film. The reaction were carried out under UV illumination for 2 h before continuing without the illumination (dark condition) for another 2 h. NiO/TiO₂ showed photcatalytic properties even without illumination implying that the energy stored during the illumination drove the photocatalytic reaction.

Abstract: A logical net element model is defined according to logical Petri net in this paper.On the basis of logical expression reasoning, the compositional operations and matching patterns of LNEs are presented. Some sufficient conditions to judge the matching pattern of two composite LNEs are obtained by theorems.

Abstract: The relationship between leaf shape and tree profile is discussed in this paper at first. Through analysis of Leonardo’s rule, Fibonacci sequence and growth regulation, we conclude that leaf shape is related to sunlight, tree profile, and the distribution of leaves. Then by constructing an integral equation of the leaf-mass density, a mathematical model is established to estimate leaf mass of a tree when the density nearly obeys gamma distribution. At last, some numerical experiments are presented to confirm the proposed model.

Abstract: After a deep investigation on the nth canonical roots of matrices, we establish the key theorem concerning how to find the n-th canonical roots. Relationship between canonical roots of a complex matrix and its n-th roots is also investigated.. Existence of canonical roots is not true for arbitrary matrix. By investigating the extension rule, this paper introduces the concept of canonical roots and gives an algorithm determining the form of canonical roots.