Advanced Materials Research Vols. 239-242

Abstract: Carbon-doped LiFePO₄/C cathode materials for lithium power batteries were prepared by liquid-state precipitation reaction. Their properties were studied by using XRD, SEM, elemental analysis, FTIR and A.C. impedance tests. The results showed that the samples with olivine structure and 3.4V discharge platform. The tapped density of LiFePO₄/C sample could reach 1.42g/cm³, and it had an initiate capacity of 144.6mAh/g at 0.2C, and 93.2% of which remained after 20 cycles. The first discharge specific capacity is 133.5mAh/g at 10C and the capacity decreased 8.76% after 20 cycles.

Abstract: Taking Cu(CH₃COO)₂·H₂O and activated carbon (AC) which was treated by acid and alkali as raw materials. The polylol reduction method was then adopted to prepare the cuprous oxide and activated carbon composite material. The structure and morphology of composite material samples were characterized by BET, SEM and XRD. The effects of cuprous oxide and activated carbon composite material on reducing the hazards of hydrocyanic acid in the cigarette were studied. Different pretreatment methods and the effect of mixture ratio to drop focal relieving harm of hydrocyanic acid in the cigarette were examined.

Abstract: Zn-Se/stainless steel thin films were prepared by ultrasonic electrochemical deposition and the application of them was discussed. Firstly, the parameters of the ultrasonic electrochemical deposition were optimized, and the morphology and component of Zn-Se thin films prepared were analyzed by SEM and EDS, it may be seen that more appropriate Zn-Se thin films were prepared by ultrasonic-electrodepositing method. Secondly, Zn-Se thin films may be applied in the aspect of treatment wastewater. Effect on treatment of Rhodamine B imitative wastewater was investigated, which ultrasonic electrodepositing method was better than traditional electrodepositing method.

Abstract: PPTA fibers made by China ShenMa Group Co., Ltd and Kevlar49 fibers made by Dupont as experimental materials were used in this paper. The differences of molecule structures were contrasted through infrared spectrum and degree of polymerization-counting by the detections of viscosity. The PPTA fibers were put into distilled water and seawater made by ourselves respectively, then ultrasonication were used to deal with them. After this, using the SEM to observe, found that the cracks appear on the fibers surfaces, presented the fibrillation and plush-like microfine fibers. Meanwhile the strength weak-link increased and breaking strength and elongation at break of fibers lowered after ultrasonication. Molecular kinetic theory was used in this paper to study loss of fibers the mechanical property.

Abstract: Nearly stoichiometric TiN_x films were deposited on Al₂O₃ substrates by laser enhanced chemical vapor deposition (CVD) with tetrakis (diethylamido) titanium (TDEAT) and ammonia as the source materials. Emphases were given on the effects of laser power (P_L) and pre-heating temperature (T_pre) on the composition and deposition rate of TiN_x films. Single phase of TiN_x films with columnar cross section were obtained. The ratio of N to Ti in TiN_x films increased with increasing P_L and was close to stoichiometric at P_L > 150 W. The deposition rate of TiN_x films with a depositing area of 300 mm² was about 18-90 µm/h, which decreased with increasing P_L and T_pre.

Abstract: In presence of nano-In₂O₃ which were synthesised via a reverse microemulsion, Polyaniline/nano-In₂O₃ composites were prepared by in-situ polymerization of aniline in 5-sulphosalicylic acid(SSA) aqueous solution. They were characterized by means of TEM, XRD and FTIR.. TEM and XRD showed that the average diameter of In₂O₃ particles was 15nm with a narrow size distribution and with a high degree of crystallization. The FTIR suggested that the structure of PAn-SSA was not be changed by the mixture of In₂O₃. Sensitivity of the composites to 100~1000ppm NH₃ were studied, the results reveal that polyaniline/nano-In₂O₃ composites have short response time and good reversibility, the gas sensitive of composites to NH₃ under 300ppm increased linearly with the increasing concentration of NH₃ and decreased with the increasing of In₂O₃ concentration. Long-term stability of polyaniline/nano-In₂O₃ composites were also investagated, it can be concluded that the organic-inorganic hybrid materials have better environmental stability.

Abstract: The electrochemical behavior of nucleobases has been studied in 0.1 M phosphate buffer solution (PBS), pH 7.4 without removing oxygen, using glassy carbon electrode (GCE). Cyclic voltammetry (CV), electrochemical impedance experiment (EIS) and square wave voltammetry (SWV) were employed in the measurements of the nucleobases electrochemical signals at GCEs. Guanine (G) and adenine (A) produced well-defined oxidation peaks at about +0.66 and +0.96 V under the CV sweep at 100 mV/s, respectively. SWV was particularly useful in investigating the electrochemical behaviour of pyrimidine bases. In the SWV detection, thymine (T) clearly appeared an oxidation peak at 1.1 V, while cytosine (C) and uracil (U) did a complex oxidation peak at 1.3 V. Nucleobases possess an irreversible and adsorption-controlled electrochemical process at GCEs in 0.1 M PBS (pH 7.4). The average surface concentrations (Γ) of G and A on the surface of the GCE were estimated to be about 1.6515×10⁻¹⁰ and 8.8232×10⁻¹¹ mol/cm², respectively. Due to the selective interactions of nucleobases with each other, the nucleobase oxidation peaks shift and new oxidation peaks appeared. The new oxidation peaks at +1.62 and 1.55 V may correspond to the oxidation of GC pairs and AT pairs, respectively. The detection of the electrochemical behaviour and selective binding of nucleobases in a physiological PBS at pH 7.4 is of particular interest for electrochemical sensor applications in physiological media.

Abstract: The NiP/TiO₂ bilayer coatings were prepared on low carbon steel substates using a combined electroless plating and sol-gel method. The performance of photocathodic protection of the bilayer coatings was investigated by the electrochemical method. The results show that the coating with four TiO₂ layers and calcined at 400°C exhibits the highest photoelectrochemical efficiency and the best corrosion resistance property.

Abstract: Effect of rare earth yttrium on the properties and microstructure of Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy was investigated. The results showed that Cu-0.6Cr-0.15Zr-0.05Mg-0.02Si alloy obtained good comprehensive performance after 80% deformation and then aging at 480°C for 1h, the hardness and electrical conductivity reached 152HV and 85.5%IACS, respectively. The aging time of Y-containing alloy for attaining peak hardness was postponed and the precipitates were finer (2-4nm) and interparticle spacing was shorter than ones of Y-free alloy. The hardness and electrical conductivity of the Y-containing alloy after 80% deformation and then aging at 480°C for 45 min reached 174HV and 82.1%IACS, respectively. The tensile fractures of the two alloys which exhibits the obvious feature of tough fracture.

Abstract: In this dissertation, the electric arc spraying coatings on steel structure were sealed over with the organic coatings addition with nano-sized TiO₂, SiO₂. Some means as light microscope, SEM, energy spectrum and binding force tests were adopted for research the permeability of the sealer. The mechanism for permeable closeness of the sealer was mainly discussed. The results indicated that homogeneous nanofillers can improvement the runnability and permeability of the epikote, stiffen the adhesion between the coatings and the metal substrate. The coating can seal the metal substrate effectively; enhance the protective property of the tectonic systems with electric arc spraying coatings and organic coatings.