Papers by Author: Wei Liu

Abstract: Anhydrite powders with nanostructure surface were prepared in Ca(OH)2-H2O-CO2 system. The effects of preparation parameters such as Ca(OH)2 concentration, revolution speed of mixer, temperature on surface finish and reaction speed were investigated. SEM was used to observe the changes of the morphology of anhydrite powders before and after surface coating. The results show that the appropriate condition is: the concentration of Ca(OH)2 should be 2~3%, the temperature between 20~25°C is better, the revolution speed should be big enough and so on. In order to gain nanostructure surface, appropriate technological parameter should be chosen carefully. The SEM photographs show that Anhydrite powders had fine surface morphology after surface finish that the smooth cleavage planes were coated with nanometer particles and the sharp edge angles were blunt by the coating of CaCO3 nanometer particles.

Abstract: By means of SEM, the micro-morphology of silver particles separated from borosilicate glass by the heat-treatment with an electric field is investigated. The distribution of the silver particles appears clusters. This result is explained by an energy viewpoint. Based on hermodynamics theory of phase separation, the calculation of the free energy change during the heat-treatment in an electric field is performed by means of the Ansoft Maxwell software. The results of this calculation analysis are found to be very close to the experimental data.

Abstract: YBa2Cu3O7-δ(YBCO) films with highly biaxial textures were deposited on SrTiO3 single crystal, textured polycrystalline Ag and NiO/Ni substrates using pulsed laser deposition, metal-organic decomposition and ultrasonic spray pyrolysis method. The microstrains in different specimens with strong textures were measured using x-ray diffractometer and were compared each other.