Advanced Materials Research Vols. 418-420

Abstract: The three common frequency selective surface (FSS) structure, i.e. ring, crosses and Y-aperture which have the same center frequencies are designed, then the three FSS structures are placed at absorbing materials to form complex absorbing structures which are simulated by means of spectral domain approach. Therefore, the effects of different FSS on the characteristics of absorbing materials are studied and the influence laws are given. This research offers reference to element selection for the application of common FSS to absorbing materials.

Abstract: The cobalt-based FT catalysts, in which Co crystals supported on TiO₂ nanofibers, were prepared by convenient method. The structure of the catalysts was examined and cobalt-based catalysts using TiO₂ nanofibers as a support for the application of FT were investigated. Based on CO hydrogenation, the cobalt species dispersed on the TiO₂ nanofibers have higher selectivity and activity.

Abstract: The shear modulus of PVB and SGP interlayer is analyzed. With the same conditions of load duration and temperature, the shear modulus of SGP interlayer is about fifteen times than that of PVB interlayer. A finite element model of laminated glass is established in this paper. The simulation results show that the maximum principal stress contours of PVB laminated glass change from a circular to a petal-shaped one and those of SGP laminated glass change form a quadrangular to a square-shaped one when the temperature rises from 20 degrees Celsius to 50 degrees Celsius.

Abstract: The influences of Nb₂O₅ on the phase, microstructure and hydrochloric acid corrosion behaviors of Nb₂O₅-Al₂O₃ ceramics sintered with 2.45 GHz microwave energy were investigated. The results showed that Nb2O5 reacted completely with Al₂O₃ to form AlNbO₄ and densified the pure Al₂O₃ at a lower sintering temperature and in a short sintering time. Nb₂O₅-Al₂O₃ ceramic samples were corroded in diverse concentration hydrochloric acid for different time. Weight loss rate of Nb₂O₅-Al₂O₃ ceramic rose dramatically when the corrosion time was not longer than 4 h, and it increased slowly beyond 24 h. After Nb₂O₅-Al₂O₃ ceramic samples were corroded for 1 h, pitting corrosion was observed by scanning electric microscope, which was consistent with the analysis results of the scanning Kelvin Probe.

Abstract: The Cobalt (Ⅱ) Complex constructed with 5-nitroisophthalic acid and 2,2’-bibenzimidazole, [Co(H2bibim)2( 5-nipa)] (1), (H2bibim =2,2’-bibenzimidazole, 5-nipa=5-nitroisophthalic acid) have been synthesized by hydrothermal methods and structurally characterized by elemental analysis, IR and X-ray single crystal diffraction. Complex 1 has six coordinated by two H2bibim ligands and one 5-nitroisophthalic acid groups that is further connected though intermolecular hydrogen bonds and resulting in a three-dimensional (3D) network.

Abstract: Laser processing ceramic materials is a new application of laser technique. This paper presents the study of making cracked glaze surface by laser processing. Proposed the applicable the composition of glaze, the main processing parameters of laser processing, and discussed the factors which may affect the quality of cracked glazing surface. It indicates that laser processing could be a new and easy processing method to produce the cracked glazing on the ceramic surface.

Abstract: CZTS thin films are fabricated by sulfurizing co-sputtered metallic precursor CuZnSn layers under H2S atmosphere. The precursor layers are Cu-poor, Zn-rich deposited and the fabricated films are about 2 µm in thickness. A closed-tube process is preferred with regard to its producing large closely pack grains with smooth surface. XRD and Raman confirm the CZTS structure and the impurities on the surface are removed after suitable chemistry treatments. The band gap of the CZTS is determined to be 1.48 eV by extrapolation. Some more CZTS films are product with slightly changed parameters, sulfurization time, temperature and concentration of H₂S, respectively. It is supposed that beside sulfurization time, the temperature could be more significant than concentration of H₂S in the closed system.

Abstract: Finite element simulations are widely used in the analysis of bird strike events in the literatures. While the shapes of the artificial birds used in the simulations are not indentical. In order to investigate the effects of artificial bird shapes on the response of laminated aircraft windshield, the often used shapes including hemispherical-ended cylinder, straight-ended cylinder and ellipsoid are modeled in this work. The striking velocity is 80.6 m/s and the SPH method is adopted. Based on the calculation results, the impact force, dissipated energy and major principle stress in the glass are analyzed. The analysis shows that the initial contact area would affect the values of these results. The shapes and aspect ratios affect the results through the initial contact area.

Abstract: The microstructured samples were prepared by irradiating silicon surface with picosecond laser pulses in SF6. The surface morphology of microstructured samples irradiated at different laser fluence was characterized by SEM. The samples exhibited high optical absorptance over a wide wavelength range between 300 and 2700 nm. The absorptance of samples irradiated with the fluence of 1.0 J/cm² was measured to be up to 95% between 1100 and 2700 nm. The infared absorptance of the surface-structured samples increased with increasing fluence. Whereas, as the annealing temperature was increased, the infared absorptance of the samples irradiated at the same fluence decreased. A tentative explanation for the effects of laser fluence and annealing temperature on the infared absorptance has been proposed based on the formation of mid-band gap impurity bands and the multiple reflections of light between microstructures.

Abstract: The stimulation mechanisms of sodium dodecyl sulfate (SDS) nanoemulsion in tight gas reservoir were analyzed by capillary force, core spontaneous imbibitions, cleanup effect and core flow experiments. The results show that SDS nanoemulsion could hold back capillarity effectively, reduce the water absorption and reduce water block damage. The initial water saturation of core decreases by 85.12% and the gas effective permeability regains by 42.03%, which improves the stimulation effect in tight gas reservoir substantially