Advanced Materials Research Vols. 239-242

Abstract: An unsymmetrical diarylethene derivative bearing both phenyl and thiophene moieties, in which a methoxyl group was substituted at the para-positions of the terminal phenyl ring, was synthesized. At the same time, its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 497 nm in hexane and at 510 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 408 nm when excited at 361 nm.

Abstract: A new photochromic compound 1-(2-ethyl-3-benzothienyl)-2- (2-n-propyl-5-formyl-3-thienyl) perfluorocyclopentene (1a) was synthesized, its photochromic properties were examined, the result indicated that the color of the compound 1a changed from colorless to a blue one upon irradiation with 297 nm UV light, a new absorption maxima were observed at 578 and 587 nm in hexane and PMMA film, respectively. The diarylethene 1a exhibited relatively strong fluorescence in hexane solution and the fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. This new photochromic compound also exhibited remarkable holographic optical recording character.

Abstract: In this paper, Sm_0.5-xGd_xSr_0.5CoO_3-δ (SGSC, x=0 and 0.2) powders were prepared using the solid-state reaction method. Their structure was identified by XRD. All powders formed the perovskite phase when calcined at 1100°C for 5 h. Sm_0.3Gd_0.2Sr_0.5CoO_3-δ/Gd_0.1Ce_0.9O_1.95 slurries were screen printed onto both surfaces of Gd_0.1Ce_0.9O_1.95 electrolyte and fired at different temperatures to fabricate the composite cathodes. The electrochemical property of the composite cathodes was characterized by the alternative current impedance spectroscopy. The impedance resistance of the composite cathodes increased with the increase of sintering temperature. For instance, the impedance resistance of the composite cathode fired at 1000 °C was 0.0875 Ω·cm² at 700 °C, while it was 0.175 Ω·cm² when fired at 1100 °C.

Abstract: On the base of the domestic and international studies, the effect of high-pressure treatment on maturation is analyzed in this thesis. In order to evaluate the quality’s changes of Gouda cheese with different high pressure treatment (50MPa, 225MPa, 400MPa treating 60min) during ripening period, the change of texture properties, microstructure and sensory analysis were measured. High pressure treatment for 60 minutes can accelerate cheese maturing significantly when the applied pressure is higher than 225MPa. The effect of accelerated ripening at 50MPa is not significant. The quality of Gouda cheese treated at 400MPa is the best after ripening 90d.

Abstract: Along nucleation → crystalline growth →crystalline fraction → critical cooling rate, the relationship between the nucleation, elements, cooling rate and the Glass Forming Ability of (Cu-Zr) based glass alloys is quantitatively studied with thermodynamics method, and a better method to evaluate the critical cooling rate of glass alloys is also proposed in this paper. The computed results show that: (1) with the increase of element number, the steady state nucleation rate drops gradually. From Cu-Zr, Cu-Zr-Al, Cu-Zr-Al-Ni, to Cu-Zr-Al-Ni-Ti, the peak value of nucleation rate decreases from 10²¹ mol^-1s^-1 to 10¹³ mol^-1s^-1. It is also found the nucleation rate both drops with the substitution of Ni with Cu or Al with Zr; (2) with the increase of cooling rate, the nucleation rate drops sharply. When the cooling rate reaches 10³K/s, the nucleation rates of Cu₆₄Zr₃₆, Cu₅₄Zr_42.5Al_3.5, Cu₅₅Zr₄₀Al₅ and Cu₃₀Zr₅₅Al₁₀Ni₅ drop to 10⁹mol^-1s^-1, 10⁶mol^-1s^-1, 10⁷mol^-1s^-1 and 10³mol^-1s^-1 accordingly.

Abstract: Transparent and conductive c-axis oriented aluminum-doped zinc oxide (AZO) films have been prepared on glass substrate by dc reactive magnetron sputtering process. The structural, optical and electrical properties of the films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), UV-Visible spectrophotometer and Hall effect measurement system. As the substrate temperature increased, the results showed that grain size of the AZO films gradually increased, the films had a strong c-axis oriented and the crystallization of films became better. The absorption edge first shows a red shift, and then switches to the blue shift with increasing substrate temperature. Optical band gap of AZO films first decreases and then increases with increasing substrate temperature. Resistivity of AZO films decreases with increasing substrate temperature but the rate of decline of resistivity becomes slow after substrate temperature reaches 250 °C. The carriers concentration of AZO films increases with substrate temperature increase.

Abstract: Fuel rods in nuclear power plants, made of Zr-alloy is immersed in pure water, and surging of this coolant causes fretting for the rods and spacer. In this paper fretting wear and fretting corrosion test of the Zr-alloy against Al₂O₃ placed respectively in air, pure water and Na₂SO₄ solution is carried out. The lost volume is measured with 3D Measuring instruments and the relationship between the fresh surface fretting wear produces and lost surface is evaluated with the potential pulse method. The result shows that the fresh surfacing area is smaller than abrasion mark area, and bigger than actual contact area. The wear extent of Zr-alloy against Al₂O₃ in Na₂SO₄ solution is ten times higher than that in air and pure water, but the coefficient of friction is smaller. The wear extent of Zr- alloy against Al₂O₃ in pure water is equal to the numeric value of the Zr-alloy against Al₂O₃ in Na₂SO₄ solution given the -2000mv potential. When Zr-alloy is in corrosion environment, the wear extent increases in proportion to the increase of the potential, and the fretting wear and fretting corrosion result from mainly electrochemical action.

Abstract: Activated carbon fiber (ACF) supported TiO₂ photocatalyst was prepared by sol-gel-adsorption method. The state of TiO₂ supported on the ACF was observed using a scanning electron microscope. Photo catalytic activity of the catalyst was evaluated by degradation of methylene blue in water, and the ways in which the efficiency of methylene blue degradation was influenced by TiO₂ load content and pH value were investigated. The supported catalyst shows cooperative effect of ACF adsorption and TiO₂ catalytic activity, and the catalytic activity of the supported catalyst was basically unchanged after using for four times.

Abstract: Calcium carbonate was obtained by the microwave-assisted hydrothermal synthesized technique using calcium chloride and urea as the raw materials. The uniform aragonite hexagonal columnar-shaped calcium carbonate with a diameter of 3.0~4.0μm and 70~120μm in length were produced without any additives at the molar ratio of urea and calcium chloride 1.5:1, microwave power 600W. The morphology, size and crystal structure were characterized by means of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR).The formation process of aragonite hexagonal columnar-shaped calcium carbonate was discussed.

Abstract: Sintered NdFeB permanent magnet is widely used in many applications because of its excellent magnetic property. But its poor corrosion resistance has been cited as a potential problem with its use.Nickel phosphorus (Ni–P) alloys systems are very attractive due to their good corrosion and wear resistance behavior. In this paper the ultrasonic effect is used in electro deposition. Experimental results show that the ultrasonic improve the deposition surface quality.