Applied Mechanics and Materials Vols. 513-517

Abstract: Supercritical CO₂ is nontoxic, nonflammable, noncorrosive, inexpensive, and does not generate any additional toxic or hazardous wastes. In this article, the fluidic parameters of supercritical CO₂ and water fluidic are calculated by related equations. The results show that the fluidic impact force of supercritical CO₂ fluidic is higher than water fluidic, which indicates that using supercritical CO₂ fluidic to dispose the obsolete propellant is possible.

Abstract: GLQ propellant is a new type of energetic material, extensive research indicates that the traditional methods evaluating the stability of this propellant are unsuitable. So in this article, the stability of this material was studied by aging test, methyl-violet test and gas phase chromatography test. The results show that gas phase chromatography test is feasible for evaluating the stability of this material, but methyl-violet test is unsuitable.

Abstract: A series of Fe-Pt based alloy films were deposited on glass substrates by DC magnetron sputtering. It is found that the Fe₃Pt and FePt₃ phases appear in Dy-addition films at first and then a composition reaction Fe₃Pt + FePt₃ FePt occurs at 500°C as annealing time increase. It suggested that Dy element can restrain the fct phase forming but help to form Fe₃Pt and FePt₃ phases. Coercivity and remanence ratio of Dy_xFe_50-xPt₅₀ alloy films annealed at 500°C for 200 h achieve the maximum 11kOe and 0.89 as x =1.5, respectively.

Abstract: In this paper, the CF/PSE-C composite is studied and tested: its characteristics of water absorption before and after the treatment of plasma are determined; the mechanical properties of the composite after water absorption are analyzed and its retention rate of mechanical strength after the absorption is compared. Results show that the water absorption of CF/PES-C composite which has been treated by plasma for 15 minutes is lower and the speed of absorption is slower while retention rate of mechanical strength after absorption is high. The CF/PFS-C resin matrix composite produced after plasma treatment is thicker and the interface pore between CF and PES-C resin matrix becomes smaller, which improves the composites moisture and heat resistance.

Abstract: The crystal growth kinetics in the deeply undercooled Zr₅₀Cu₅₀ melt was studied with the electromagnetic levitation technique. The maximum growth rate u_max was, for the first time, demonstrated in undercooled metal and alloy melts, and this allowed us to construct the complete profile of crystal growth kinetics in the whole undercooling region of Zr₅₀Cu₅₀ melt. In deep undercooling region near glass transition, the diffusion-controlled crystal growth mechanism accounted for the growth kinetics, while at lower undercooling the profile around u_max remarkably differed from what the classical growth theory covers.

Abstract: This paper analyses the mechanical properties and pavement performances of road base with cement stabilized iron tailings sand mixture based on the experimental research. It discusses the feasibility whether iron tailings sand can be used in road base.

Abstract: According to the principle of dynamic quenching a new ON-OFF fluorescent chemosensor for Cu²⁺ ions was designed, this chemosensor was composed of p-tert-butylthiacalix [arene (TCA),sodium dodecyl sulfate (SDS) and perylene through the form of self-assembly in aqueous solution. Addition of Cu²⁺ ions could result in a quenching of the fluorescence emission of perylene inside micelles, which due to intramicellar complex-fluorophore electron-transfer or energy-transfer effects induced by the complexation of TCA with the Cu²⁺ ions.The experimental results indicated that: Under the condition of TCA/perylene was 800/1, SDS concentration was 150mmol/L and pH value above 9, according to the fluorescence quenching ,within a certain range of the concentration of Cu²⁺ ion can be linearly determined.

Abstract: The magnetism of Y doped ZnO film was calculated by using an accurate full-potential linerized plane-wave and supercell method. To analyzing the results, we find that: The ZnO film containing Zn vacancies is magnetic and the origin of magnetism is Zn vacancies; The Y ions in Y doped ZnO film is +3 and non-magnetic; The formation energy of Zn vacancies in the Y doped ZnO film is smaller than in the ZnO film, so Y favors the formation of V_Zn; The Y doped ZnO film containing Zn vacancies is magnetic.

Abstract: Surface and subsurface defects of optics are of major concern in improving laser induced damage threshold. SiO₂ single layers were fabricated by physical vapor deposition and sol-gel technique on fused silica substrates. HF acid etching and ultrasonic cleaning process are used to investigate the effect of surface and subsurface defects of substrates on the laser induced damage threshold (1-on-1, 8 ns at 355nm). Experimental data are then fitted with the Gaussian model of threshold distribution, which permits to discriminate different kinds of defects and extract their densities and threshold distribution. The interpretation of these data is further discussed according to their cleaning and fabrication method.

Abstract: Well-dispersed α-Fe₂O₃ nanocrystalline was prepared by a convenient self-propagation combustion method using low-toxic glycine as fuel, low-cost Fe (NO₃)₂·9H₂O as raw materials. The XRD results indicate that the glycine doses have an important effect on the control of the average size and the order of the crystalline phase. The UV-vis results indicate that the α-Fe₂O₃ nanocrystals prepared by this method have a broad absorption peak whose center is at about 221 nm. TEM images revealed that the products were composed of well-dispersed particles with an average size about 35 nm.